MLB Rookie Power Rankings: Paul Skenes arrives and a new leader emerges in May

A flip of the calendar from April to May demonstrated just how volatile rookie performances can be from one month to the next. 

Paul Skenes announced his arrival with authority, Rookie of the Year favorite Shōta Imanaga hit his first roadblock in his 10th start of the year and a new leader emerged from the pack in FOX Sports' second rookie power rankings of the year, which feature some sizable jumps forward, notable drops down and a handful of new names. 

(Note: The rankings below will be updated once a month throughout the season.)

Honorable mentions

- Jackson Merrill (OF, San Diego Padres
- Wenceel Pérez (OF, Detroit Tigers)
- Colton Cowser (OF, Baltimore Orioles

Merrill leads all rookies in hits, though he has struggled to both reach base and hit for power lately. Still, his batted-ball data and ability to make contact suggest the 21-year-old should be much better than a league-average hitter. Plus, his terrific defense in his first year as a center fielder is worth noting. 

Perez's transition from infielder to outfielder is a work in progress, but the bat is there. Whether hitting from the left side or right, the switch-hitter has produced. It says something about the Tigers' confidence in the 24-year-old that the majority of his at-bats this year have come in the No. 3 spot of the order. 

Cowser has really struggled to produce in May after his blistering start to the season, but the fact that he has a meager .169/.286/.260 slash line this month and still ranks fifth in slugging and sixth in OPS overall this year among all qualified rookies demonstrates just how good he was while taking home Rookie of the Month honors last month. His batted-ball data suggests he should be slugging much higher than his .444 mark, so I'd expect him to work his way back into the top 10. 

10. Ben Brown (P, Chicago Cubs)

Previous Ranking: N/A

Brown has bounced between starting and relieving this year, but after his latest outings, he should be doing a lot more of the former and deserves a spot on the updated top 10. The right-hander followed up two scoreless innings of relief against the Pirates with four scoreless innings in a start against the Braves. He then held the Brewers hitless through seven scoreless innings with 10 strikeouts in his most recent start. Since a troublesome debut, Brown has a 1.61 ERA in his last 12 appearances (six starts). He has a 1.16 ERA with 33 strikeouts in 23.1 May innings. 

9. Jared Jones (SP, Pittsburgh Pirates

Previous Ranking: 2

Jones' velocity was down a tick in his worst outing of the year Wednesday against the Tigers, which knocked him down a few pegs here. More troubling, he only got four swings and misses in the outing. Until this week, though, he had always managed to give the Pirates length. Wednesday was the first time the right-hander had gone fewer than five innings in a start this year, and prior to that performance, each of his first four starts of the month were quality starts. Jones has experienced some issues with the long ball, but he ranks second among all qualified rookie starters in both strikeouts and strikeout-to-walk ratio.

8. Yoshinobu Yamamoto (SP, Los Angeles Dodgers

Previous Ranking: 4

Though still primarily a three-pitch pitcher — fastball, splitter, curveball, plus the occasional cutter — Yamamoto has tinkered with his mix, adding a slider and sinker to combat righties after they hit him hard in April. Now, though, lefties are getting to him in May, and the splitter that was so unhittable in April hasn't been nearly as effective. This all seems to be part of the feeling-out process for Yamamoto as he adjusts to life as a big leaguer. Though he has struggled more than usual over his past three starts, he remains one of the top rookie pitchers in the sport with numbers eerily similar to Jones'. 

7. Joey Ortiz (3B, Milwaukee Brewers

Previous Ranking: N/A

Milwaukee fans sad to see Corbin Burnes go now have a reason to smile. DL Hall might have taken more of the attention when the trade was made, especially since he cracked the rotation, but it's Ortiz who has taken his opportunity and run with it. Known more for his glove as an infield prospect in the Orioles' deep farm system, Ortiz has been baseball's best rookie hitter in May. While he could be due for some regression from the phenomenal .954 OPS he has put up this month — he's producing better than his expected stats would suggest — his adjustments in approach have led to him chasing less, whiffing less and walking more than he did in the high minors. It'll be interesting to see if he can keep that up, but regardless, he's providing a ton of excitement for the future in Milwaukee. 

6. Paul Skenes (SP, Pittsburgh Pirates) 

Previous Ranking: N/A 

Is it too soon to put him in the top 10? I don't think so. Since his abbreviated debut, Skenes has a 1.50 ERA while striking out 23 batters in 18 innings over his past three starts. The same Tigers team that Jones struggled to put away in the first game of Pittsburgh's Wednesday doubleheader whiffed 19 times and struck out nine times in six innings against Skenes in Game 2, and it's not all about the gas (although that is plenty entertaining). Skenes got 11 whiffs on his "splinker" and used the pitch more than his four-seamer in the start. The only game the Pirates have lost with Skenes on the mound came when the bullpen blew a four-run lead. We'll soon be talking about him as one of the top pitchers in the sport, if that's not happening already. 

5. Masyn Winn (SS, St. Louis Cardinals)

Previous Ranking: 7

Winn hasn't just gotten by as a major-league hitter; he has thrived. Amid an 18-game hitting streak, the hard-throwing shortstop has answered any questions about how his bat would play at the highest level. By bWAR, Winn has been the most valuable rookie position player in baseball this year. He doesn't hit the ball hard, but he also doesn't whiff or strike out. His ability to make contact despite a relatively high chase rate and spray line drives and grounders to all fields allows him to utilize his tremendous speed. Winn leads all qualified rookies in batting average — by far — and is second in hits, doubles and on-base percentage.

4. Wilyer Abreu (OF, Boston Red Sox) 

Previous Ranking: 5 

Abreu leads all qualified rookies in doubles and slugging percentage and ranks in the top three in every slash line category. He's basically above average in every facet as a hitter, baserunner and fielder. He hits the ball hard, draws walks, steals bases, plays a strong corner outfield and has a howitzer for an arm, which is why he leads all qualified rookies in fWAR. The 24-year-old has been remarkably consistent. After posting an .862 OPS in 28 games last year, he has an .866 OPS through 49 games this season. 

3. Mason Miller (RP, Oakland Athletics)

Previous Ranking: N/A

Miller was a perfect 11-for-11 in save opportunities until suffering his first blown save Thursday. No other rookie in baseball has more than two saves. Of the 12 other relievers with at least 11 saves this season, Andres Muñoz has racked up the most strikeouts with 33; Miller, meanwhile, has 51. Since allowing two runs in his first outing of the year, Miller has a 1.44 ERA and has held his opponent scoreless in 17 of his 19 appearances while racking up exactly twice as many strikeouts (50) as innings pitched (25) during that stretch. His whiff rate is almost double that of the MLB average. I mean, just look at this

(For those wondering, Miller does indeed still qualify as a rookie this year after coming very close to exceeding the limits for time spent on an active roster last season.) 

2. Shōta Imanaga (SP, Chicago Cubs) 

Previous Ranking: 1

Imanaga would've still ranked first on this list until this week, when he allowed seven earned runs — two more than he had surrendered in his first nine major-league starts combined — in a 10-6 defeat to the Brewers. His first loss saw his ERA rise from 0.84 to 1.86, which still ranks first among all qualified rookie starters. Imanaga lives in the zone, which helps him limit walks and get a lot of chase when he decides to go a bit higher with his elite four-seamer or drop his splitter low. It also, however, made him prone to home runs while pitching in NPB. He had mostly avoided that issue in his move to the majors, allowing three home runs total on the year until serving up two on Wednesday. Prior to the start, Imanaga had given up just two runs in 26 innings in May and looked to be on pace to be the first Rookie of the Year and Cy Young Award winner since Fernando Valenzuela. That feat will be more difficult now, though it's still possible if he can bounce back from his first real clunker.

1. Luis Gil (SP, New York Yankees

Previous Ranking: N/A

I'm not entirely sure what the Yankees are going to do whenever Gerrit Cole returns, but I don't know how they take Gil out of the rotation at this rate. He just wrapped up May with a 6-0 record, a 0.70 ERA and a 0.67 WHIP while going at least six innings in each of his six starts during the month. On the year, the 25-year-old is 7-1 with a 1.99 ERA and 0.95 WHIP. His 79 strikeouts rank first among all qualified rookies, and his .135 opponents' batting average ranks first — by far — among all qualified MLB starters. He racks up strikeouts with his high-velo four-seamer, and opponents are hitting under .150 against his changeup and slider. 

Also considered: Michael Busch (IF, Chicago Cubs), Colt Keith (INF, Detroit Tigers), Simeon Woods-Richardson (SP, Minnesota Twins), Bryan Hudson (RP, Milwaukee Brewers), Gavin Stone (SP, Los Angeles Dodgers), Andy Pages (OF, Los Angeles Dodgers), Jacob Young (OF, Washington Nationals), Kyle McCann (C, Oakland Athletics), David Hamilton (Boston Red Sox), Mitchell Parker (SP, Washington Nationals)

Rowan Kavner is an MLB writer for FOX Sports. He previously covered the L.A. Dodgers, LA Clippers and Dallas Cowboys. An LSU grad, Rowan was born in California, grew up in Texas, then moved back to the West Coast in 2014. Follow him on Twitter at @RowanKavner.