On the surface, a light-hitting infielder with one career home run and average speed doesn’t sound all that entertaining to watch and follow as a prospect. Yet, “entertaining” is pretty much the best way to describe the Rumble Ponies’ shortstop, Luis Guillorme. Guillorme—a Spring Training celebrity after catching a flying bat in the dugout—brings one of the best defensive games in all of professional baseball to the table. He has impressively quick hands and excellent reaction times that allow him to dazzle defensively without exceptional speed or athleticism. The biggest question for Guillorme in 2017 and going forward remains his bat, which is the final obstacle standing between the former 10th round pick and Queens. While he will never be confused for a power hitter, Guillorme’s .052 ISO in St. Lucie in 2016 would have ranked as the lowest such figure in the major leagues for any player with greater than 150 plate appearances last year. Improving his gap power while maintaining a respectably high on-base clip will be essential for Guillorme to stay on track for a major league role. And even just a passable bat could give Guillorme a real shot at having a long major league career as a defensive-minded infielder.

Although he is currently on the shelf as he recovers from a recent knee operation, Tommy John survivor Chris Flexen is among the best pitching prospects in the Mets system and perhaps the “ace” of the 2017 Rumble Ponies. Flexen, who was added to the Mets 40-man roster this winter, boasts a fastball that has touched as high as 97, and a full four-pitch repertoire that makes him an intriguing starting pitching prospect. While he is risky even by pitching prospect standards, having already undergone Tommy John Surgery and now knee surgery by the age of 22, Flexen’s current profile is not all to far off from former Mets pitching prospects, such as Robert Gsellman and Michael Fulmer, as they entered the upper minors. While Flexen has not yet consistently missed bats at a high clip, posting only a 16.6% K-rate in 134 innings for St. Lucie last season, his stuff suggests that could improve in a hurry (see: Gsellman, Robert). With his option clock now running, 2017 will be an important year for Flexen if he looks to establish himself as an emerging option in the Mets’ suddenly less crowded starting pitching situation. Given his injury history and relatively high effort mechanics, it is quite possible that Flexen’s quickest and most likely path to the major leagues will come as a short reliever. Consistency, health, and breaking ball development—well, he’s in the right org for that one— will be essential for Flexen as he looks to make an impression this season in Western New York.

Short Hops

2015 4th round pick and ACC home run champion David Thompson figures to be the everyday third baseman for Binghamton in 2017. While Thompson’s defense has been better than advertised to this point in his professional career, he must hit for more power in Binghamton if he is to continue to rise through the ranks…Northern Irish southpaw P.J. Conlon will look to continue his improbable rise to the major leagues with a stop in Binghamton to open the 2017 season. Conlon, a soft-tossing lefty with a good change, posted an incredible 1.79 ERA split between Columbia and St. Lucie in his first full professional season. Double-A is always a test for this profile…yet another fast rising member of the Mets’ 2015 draft class, Corey Taylor, joins the Binghamton Rumble Ponies. Like Conlon, Taylor has had little issue yet with professional hitters, posting a 1.87 ERA out of the bullpen for the St. Lucie Mets. Taylor’s stuff showed well in the Arizona Fall League, flashing a fastball that could bump the upper-90s and a plus slider. In an admittedly small sample size—though a very tough pitching environment— he missed bats at a higher clip (17 strikeouts in 14 innings) than he had previously in the minor leagues. If Taylor is able to keep up his stellar results and maintain his fall bump in stuff and strikeouts, he might not be long for Binghamton and could have a real shot to pitch out of the Mets’ bullpen sometime this season…center fielder Champ Stuart might be the fastest player in the Mets system and he’s a plus center fielder to boot, but he’s never shown the ability to hit offspeed and might never be more than a late-inning pinch-runner and defensive caddy. He’s ready for that role right now though and the 2017 Mets sure could use that.

Photo Credit: Steve Mitchell- USA Today Sports

Chasen Bradford: Bradford, like the majority of invitees, is a pitcher whose presence suggests the Mets are looking to bulk up the bullpen. Originally drafted in 2011, Bradford has been with the 51s since 2015. Though his ERA spiked to 4.80 in 2016, his career overall of 3.42 is stronger, and he’s shown time and again that he can handle the pressure, earning five of six saves in 2016, and 36 of a possible 48 across his career thus far.

Xorge Carrillo: The only non-roster catcher to attend spring training, Carrillo was also a 2011 Mets’ draft pick. He began in Brooklyn, and spent 2016 in Binghamton and Las Vegas, where he batted .333 and .269, respectively, slashing .257/.328/.354 over his career.

P.J. Conlon: A 23-year-old Northern Ireland-native, Conlon is an intriguing prospect beyond his heritage. The lefty was the Mets’ 13th-round draft pick in 2015, and has already played with the Cyclones, St. Lucie Mets, and Columbia Fireflies. At 5’11,” Conlon is the shortest of the pitching invitees, but so far his performance suggests he’ll be a force to be reckoned with: he’s gone 12-3 with one save and an ERA of 1.47 across 41 games.

Phillip Evans: A 24-year-old infielder, Evans was drafted out of high school in 2011, and had his best season yet in 2016 split between Binghamton and St. Lucie, slashing .321/.366/.460 with eight of his 19 career home runs. Over his five-year career, Evans has hit .255/.318/.344.

Luis Guillorme*: A 10th-round draft pick in 2013, the infielder started in the Gulf Coast League and spent 2016 with the St. Lucie Mets, where he hit his first professional home run. Guillorme hit .285/.355/.326 across his career, with 34 stolen bases.

( * – Editor’s Note: Please email Jeff Paternostro with any and all questions about Guillorme.)

Kevin McGowan: The tallest invitee on the list, 25-year-old McGowan fits neatly between other leggy pitchers Syndergaard (6’6″) and deGrom (6’4″) at 6’5”.  A 13th-round draft pick in 2013, the righty spent 2016 moving between Las Vegas, Binghamton and St. Lucie, going 5-1 with two saves and an ERA of 2.35, the best of his career so far.

David Roseboom: This lefty was a 2014 draft pick and spent 2016 in Binghamton, where he managed 14 saves (in 15 opportunities) with an ERA of 1.87 across 52 games. Over his career, he’s gone 5-3 with 26 saves and an ERA of 2.26.

Ben Rowen: Originally a 2010 Texas draft pick, the 28-year-old made his major-league debut in 2014, in an eight-game run with the Rangers. He was called up for four games by the Milwaukee Brewers in 2016. Though both his stints in the majors have been middling (and short), his minor-league stats are impressive: 25-10 with 43 saves and an ERA of 1.85. Here’s hoping a spring training invite allows Rowen time to shake loose the nerves and show the majors some of his good stuff.

Paul Sewald: This righty pitcher was a 10th-round draft pick for the Mets in 2010, and spent 2016 in Las Vegas, where he went 5-3 with 19 saves and an ERA of 3.29. Over his time with Mets affiliates, he’s gone 16-8 with 66 saves and an ERA of 2.20.

Dominic Smith: Smith is the youngest of this year’s invitees—he’ll be 21 upon his arrival in Port St. Lucie. The infielder was drafted from his California high school by the Mets in 2013, their first round pick, and just finished off a great season in Binghamton, where he hit .302/.367/.457 with 14 home runs. I’ll be excited to see how this slugger holds up when he faces off against some major-league arms.

Champ Stuart: With a name like “Champ,” he’s gotta be good! Also an early draft pick from 2013 (the Mets’ sixth-round choice), this outfielder—given name “Jervis”—split time between Binghamton and the St. Lucie Mets in 2016. He hit .240/.314/.349 with eight home runs across the two teams, and he’s lightning fast; he’s managed 40 stolen bases in 114 games.

Corey Taylor: This 24-year-old righty pitcher was a seventh-round draft pick in 2015, and has done well in his time with the Cyclones and St. Lucie Mets. Over his two-year, 63-game career, he’s gone 5-6 with an ERA of 1.77 and 20 saves.

Logan Taylor: No relation to the aforementioned Taylor above, this 25-year-old, also a right-handed pitcher, was drafted by the Mets in 2012. He went 4-2 in Binghamton in 2016 and has a career ERA of 3.26 across 99 games.

Travis Taijeron: A 2011 draft pick for the Mets, this left fielder has spent the past two years in Las Vegas, where he hit 25 home runs in 2015, and 19 in 2016, batting slightly above his career average of .269/.370/.512. This slugger’s got power, and 110 career MiLB home runs to prove it; fingers crossed his swing is just as deadly in the big leagues.

Adam Wilk: At 29, Wilk is the oldest invitee on the list. (And yet still slightly younger than I am. Sigh.). Perhaps unsurprisingly, then, he’s already got his feet wet in the majors—he had runs in 2011 and 2012 with the Tigers, and two innings with the Angels in 2015. 2016 was not his best year—he went 2-8 with the Triple-A Durham Bulls, but I’ll indulge the Mets pitching staff here in the hope he can combine the mojo from his earlier days with his major-league experience and put his best arm forward for 2017. Wilk has a career ERA 3.59 across 153 games.

Photo Credit: Reinhold Matay-USA Today Sports

Before we get started, we should probably do a brief summation of who needs to be added to the 40-man roster and why. Players are added to the 40-man to be protected from the major-league portion of Rule 5; generally speaking, 40-man eligible players are four or five seasons into their pro careers, depending on which side of 19 they signed their pro contract on. It’s terribly complicated and not that necessary to know the exact rules, because wonderful folks like Chris Walendin at tpgMets understand the rules very well and put together a comprehensive list of Met Rule 5 eligibles. Let’s go over the interesting names on there, in rough order of likelihood that they’ll end up on the Met 40-man by the third week in November.

He Will Be Added

Amed Rosario: Rosario is the best prospect in the system and will obviously be protected. He’ll only be an injury or underperformance somewhere in the infield away from his major-league debut in 2017.

They Should Be Added

Tomas Nido: Successful Rule 5 picks that stick generally fall into three categories—pitchers with big upside that can be hidden as mop-up men, polished downroster players like middle relievers and versatile utility players (the Mets kept one in this category themselves in 2015 in Sean Gilmartin), and backup catchers. Nearly every team has a roster spot open for an extra catcher, and a player like Nido who can already defend at a major-league level is really easy to carry for a season. Because of that, the Mets will likely need to add Nido. In 2016, he displayed a new ability–hitting for average–on top of his defense.

Marcos Molina: Molina has barely pitched since a dominant late-summer for Brooklyn at 2014 that established him as a top pitching prospect in the system. Chronic elbow problems in 2015 ultimately resulted in Tommy John surgery. Molina falls into the big upside pitcher that could easily be hidden throwing 60 innings of low-leverage relief, and given that he is still on the road back from TJS, he could probably have a phantom DL stint or two thrown in for good measure. The Mets sent Molina to the Arizona Fall League, tipping off that he’ll be protected because it’d be awful dumb to give other teams free looks at one of your top pitching prospects if he wasn’t already being kept. Right?

Wuilmer Becerra: The outfielder was one of the most puzzling non-protects last offseason, and the Mets probably got a little lucky that he went unpicked in Rule 5. His 2016 was weird—he hit for little power amidst shoulder problems that would ultimately end his season early, but he did hit .312 in the pitcher-friendly High-A Florida State League. It would be even more surprising if he wasn’t protected this year, assuming his medicals are fine, since his stock is up a touch and he’s had success at a higher level.

Pick Your Favorites

Chris Flexen: Flexen had a superficially unimpressive first full season back from Tommy John surgery, but as Mets fans have learned with Zack Wheeler and Bobby Parnell, unimpressive but healthy really isn’t a bad thing at all coming back from TJS. Flexen is on the lower side of the generic decent projectable righty pitcher group that the Mets have had huge success with, so they might be more inclined to protect him than another organization would be.

Paul Sewald: The Las Vegas 51s had exactly one good pitcher in 2016. It wasn’t Robert Gsellman, despite his shooting-star stock. It wasn’t Seth Lugo, the other guy who had 2016 major-league success. It wasn’t Sean Gilmartin or Logan Verrett, who had 2015 major-league success. It wasn’t really even Gabriel Ynoa. It was Paul Sewald, throwing up 11 K/9 and a 3.29 ERA in one of baseball’s toughest pitching environments. Sewald has major-league capable stuff and given his success all the way up the ladder might even be pretty decent, but he was snubbed for a September call-up that might’ve portended a 40-man add.

Kevin McGowan: McGowan went from a guy teetering on organizational pitcher to a genuine major-league relief prospect in 2016, which is a good thing. He’s probably capable of being a major-league middle reliever now, so the Mets stand a decent shot at losing him if they expose him in Rule 5. I suspect they might protect whichever one of Sewald and McGowan is viewed higher internally, but I cannot imagine both will be added to the 40-man.

Phillip Evans: He hit .335! In Double-A! He plays infield positions! Evans was once a prospect and had fallen off the radar. He hit his way back this year. He is probably more useful than the Eric Campbells of the world, but the Mets have tended to value major-league experience and clubhouse familiarity at the bottom of their roster over upside.

On The Radar

Champ Stuart: I feel like I’ve written about Champ Stuart about ten times in the last two months. He’s really fast. He’s a good defender capable of playing all the outfield spots. He can’t hit. If he was going to be added to the 40, he probably would’ve been called up like Gavin Cecchini was, because he would’ve helped an expanded roster. Ten or fifteen years ago, this type of player would have had a much better shot to go, because teams did stuff like carry fifth or sixth outfielders who can’t hit back then. Now teams carry thirteen or even fourteen pitchers, and this type of player is really hard to carry in the regular season.

Jeff McNeil: The golfer-turned-utility prospect missed essentially the entire season after undergoing hip surgery. There’s little chance he’s added, but I mention him here because there’s some chance he’s taken, since he falls into that polished utility infielder territory as a guy who can hit a little and play a lot of positions.

Nabil Crismatt: Now we’re into the land of low-level arms that would qualify as surprises; it’s worth remembering that the Mets added Seth Lugo and Jeff Walters in this kind of a spot last year. If you squint, you can make out the outline of Lugo with Crismatt: middling velocity, a big breaking curve, a good change, very good command. Of course, you could make that outline in a lot of pitchers, which was why Lugo was a weird add and an unexpected contributor.

Ty Bashlor: Bashlor got $550,000 in the 11th round in 2013 because he can throw really freaking hard. He’s only thrown 71.3 pro innings since—he’s another Tommy John survivor—and he’s now a reliever. But he also throws really hard and struck out a lot of dudes in A-ball. Probably not a great risk to go this year, but he could be a factor down the road.

Photo Credit: Gary A. Vasquez-USA TODAY Sports