Fantasy Baseball Prospects Report - MLB Rookie Risers and Fallers Include Mark Vientos, Eury Perez, Matt McLain

Welcome to RotoBaller’s Recently Promoted Prospects series for fantasy baseball! Here I discuss some recently-promoted top MLB prospects and rookies, making note of what I think their upside could be for fantasy baseball managers, and whether they are potential risers or fallers.

In the past few weeks, we have seen a few more high-impact rookies make their MLB debut. Below I discuss three rookies that will work their way into fantasy relevance. I will use industry scouting reports, analytics, and RotoBaller’s premium projections to predict what each recently called-up player could do if given a continued opportunity in 2023.

Here are your recently promoted prospects for Week 9 of the fantasy baseball season.

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Eury Perez, Miami Marlins

67% Rostered on Yahoo

Situation: Miami Marlins' top prospect, right-handed starting pitcher Eury Perez, was called up to the majors on May 12. He allowed two runs and struck out seven batters over 4 2/3 innings pitched against the Cincinnati Reds in his big league debut. In this first start, as per MLB.com, his fastball’s average spin rate (2,623 rpm) was just behind Guardians closer Emmanuel Clase (2,644) for the best mark in all of MLB this season.

Perez followed up his first start with another solid performance on May 18 against the Nationals, allowing only one earned run over five IP on three hits while striking out six. Perez, arguably the top pitching prospect in all of MLB, should now remain with the Marlins for the rest of the season.

Skill: Perez is a 6’8”, 220-pound right-hander who was signed as an international free agent by the Marlins out of the Dominican Republic. The 20-year-old is the ninth-ranked prospect in all of MLB as per MLB pipeline. Over the course of three seasons in the minors and three levels, Perez has posted an impressive 2.85 ERA, 0.98 WHIP to go with 260 strikeouts in 186 IP.

Prior to his promotion to the majors directly from Double-A, Perez had posted a 2.32 ERA, 0.82 WHIP, and 42:9 K:BB ratio over 31 IP with the Pensacola Blue Wahoos. Perez has a four-pitch plus-plus arsenal that includes a fastball that can reach 100 mph, a curveball, a slider, and a nasty changeup.

Projection: Perez, who became the youngest pitcher in Marlins history when he made his debut on May 12, is MLB-ready. This is about as clear-cut as it gets. Perez, who has been taken under the wing of Sandy Alcantara, should be immediately rostered in every redraft format. While there may be some growing pains and innings limitations, he will help managers with ratios and strikeouts. He is a priority add in all redraft formats.

Mark Vientos, New York Mets

16% Rostered on Yahoo

Situation: 23-year-old right-handed New York Mets corner infielder Mark Vientos made his 2023 MLB debut on Wednesday after tearing up Triple-A Syracuse to open the season. Vientos, who played in 16 games with the Mets toward the close of the 2022 campaign, made an immediate impact by belting a home run against the Tampa Bay Rays.

Prior to his recall, over 38 games at Triple-A in 2023, Vientos slashed an impressive .333/.416/.688 with 13 HR and 37 RBI over 141 at-bats.  He was also among the barrel rate leaders in the minors before his promotion with an 18.2 barrel percentage.

Skill: Vientos is the Mets’ seventh-ranked prospect as per MLB Pipeline. Over his six-year minor league career, Vientos has posted a .277/.348/.500 slash in 444 games. He set a career-high in homers with 25 in 2021 over 310 AB. He is well on pace to break that total this season if he gets regular playing time (he already has 14 HR between Triple-A and MLB).

There is no doubt Vientos possesses elite power though he has struggled with strikeouts over his professional career. This will serve to limit his ceiling. In his 16-game stint with the Mets in 2022, Vientos hit just .167/.268/.278 with one home run, three RBI, and 12 strikeouts (36 AB). Notwithstanding, Vientos has made strides in this department for at least the early part of 2023. His 2023 K rate is 20.5% versus a 2022 29.3% K rate.

Long term, it is doubtful that Vientos will stick at third base given defensive issues and, of course, Brett Baty’s presence on the team. In fact, Vientos’ defensive shortcomings, combined with the strikeout tendencies, are part of the reason the Mets had Vientos begin the season in Syracuse.

Projection: It was about time that Vientos got the call given the Mets' offensive struggles. Vientos should see the majority of his playing time as the Mets designated hitter, with Baty serving as the Mets' starting third-baseman (and Pete Alonso, of course, entrenched at first). It is doubtful that manager Buck Showalter will place Vientos into a platoon with Baty. It is more likely that Vientos will split time at DH with veterans Tommy Pham and Daniel Vogelbach. As a result, Vientos will probably not be in the Mets lineup regularly, unless he vastly outhits Pham and Vogelbach (certainly not out of the question).

For this reason, Vientos is a better addition in daily redraft formats. That said, he is still a must-add in all redraft formats given his power and RBI potential (20-30 HR over the course of a full season) hitting in a lineup that has recently woken up.

Matt McLain, Cincinnati Reds

40% Rostered on Yahoo

Situation: Cincinnati Reds middle infield prospect Matt McLain made his MLB debut on Monday. Prior to his promotion, much like Vientos, McLain was tearing up Triple-A slashing .348/.474/.710 with 12 HR and 40 RBI over 138 AB (38 games). McLain was promoted due to the struggles of shortstop Kevin Newman. Since his call-up, McLain is 4-for-12 with a walk, five strikeouts, and two doubles.

Skill: The 5’11”, 180-pound McLain was drafted in the first round of the 2021 MLB Draft (17^th overall) straight out of UCLA. He is the fifth-ranked prospect in the Reds’ organization, and 94^th ranked prospect in all of MLB, as per MLB Pipeline. Over his three-year minor league career, over four levels, McLain has slashed .267/.393/.512 with 32 HR, 117 RBI, 47 steals, and 41 doubles over 615 AB. McLain will become a legitimate 20-20 threat, especially calling Great American Ballpark his home.

McLain possesses solid on-base percentage skills with plus-to-elite power and speed. Unfortunately, like Vientos, strikeouts have been a thing with McLain. That said, prior to his promotion, his brutal 2022 28.1% strikeout rate from Double-A Chattanooga (127 strikeouts in 371 AB) fell to just 19.7% in Triple-A Louisville in 2023.

Projection: McLain is part of the youth movement in Cincinnati which should make the Reds an exciting team to watch for years to come. Along with Jonathan India, TJ Friedl, and eventually, Elly De La Cruz, Cam Collier, and Noelvi Marte, the Reds will be a formidable ball club in the NL Central.

McLain should remain with the Reds for the duration of the 2023 campaign. Reds' manager David Bell has already said that he expects McLain to see significant playing time at shortstop which is music to the ears of those managers who have him rostered. With Newman struggling, McLain has job security as the Reds starting shortstop hitting in the top third of the lineup. There will be growing pains for sure, but redraft managers should make McLain a priority add in all formats. He will help produce in all counting stat categories hitting atop the Reds lineup going forward.

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