Kyle Lewis' pro career didn't exactly unfold as expected because the 11th overall pick in the 2016 Draft tore up his right knee 30 games into his debut and still didn't always look 100 percent even three years later. But the outfielder made the most of a callup last September by homering six times in 18 games with the Mariners, and he ranks among the American League leaders in several categories this summer.

Lewis once again tops MLB Pipeline's Rookie Power Rankings for the third time in as many editions. While that's not much of a surprise given his pedigree and production, did anyone see the National League's top rookie coming? Offseason trade acquisition Jake Cronenworth has played four positions for the Padres and raked at all of them, and he moves up to No. 2 in the RPR this week.

Our Rookie Power Rankings are based on 2020 performance and feature four newcomers to the Top 10 this week.

1. Kyle Lewis, OF, Mariners (graduated from Top 30)
Previous Rookie Power Ranking: 1
After striking out 48 times in his first 29 big league games (including last September), Lewis has shown much improved plate discipline, which bodes well for his future. He's batting .339/.430/.543 with eight homers in 35 contests this year, including a sizzling 1.129 OPS over the last two weeks.

2. Jake Cronenworth, INF, Padres (No. 16)
Previous RPR: 4
As an infielder with solid hitting ability and speed, not to mention a fastball that reached the mid-90s when he dabbled on the mound, Cronenworth was an intriguing if not highly touted talent when the Padres acquired him and Tommy Pham from the Rays for Hunter Renfroe and Top 100 Prospect Xavier Edwards in December. If he weren't a few plate appearances shy of qualifying, he'd be leading the National League in hitting. His batting line (.361/.417/.619) compares favorably to that of double-play partner and potential NL MVP, Fernando Tatis Jr.

3. Luis Robert, OF, White Sox (No. 1/MLB No. 3)
Previous RPR: 3
The preseason favorite to win the American League Rookie of the Year Award, Robert has lived up to his billing by powering the White Sox to a tie atop in the AL Central. He leads all rookies with nine homers, including a walk-off shot on Sunday, and he's batting .291/.339/.581 with 16 extra-base hits and four steals.

4. James Karinchak, RHP, Indians (No. 15)
Previous RPR: 6
Karinchak set a modern Minor League record (minimum 30 innings) by averaging 22 strikeouts per nine innings last year, and his upper-90s fastball and hammer curveball have proven just as devastating in the big leagues. He has struck out 34 of the 66 batters he has faced this year, posting a 1.02 ERA in 17 2/3 innings as a vital member of the Indians' bullpen.

5. Tony Gonsolin, RHP, Dodgers (graduated from Top 30)
Previous RPR: unranked
A two-way player at St. Mary's who was a $2,500 senior sign as a ninth-rounder in 2016, Gonsolin added significant velocity once he became a full-time pitcher as a pro and now possesses a mid-90s fastball, a devastating splitter and a pair of power breaking pitches. He has allowed just one run in four starts this summer while striking out 17 in 17 2/3 innings.

6. Dustin May, RHP, Dodgers (graduated from Top 30)
Previous RPR: 10
One of the game's top pitching prospects before he graduated to the big leagues, May has perhaps the nastiest two-seam fastball in the game. He hasn't missed as many bats as expected but has been plenty effective, logging a 2.83 ERA with 23 strikeouts in 35 innings as the Dodgers have won five of his seven starts.

7. Josh Staumont, RHP, Royals (graduated from Top 30)
Previous RPR: unranked
Staumont had the hardest fastball in the 2015 Draft and the best pure arm in the Royals' system since he signed as a second-rounder that June, but he never has been able to throw consistent strikes. Though he has issued 11 walks in 14 2/3 innings this summer, his fastball has averaged 98.3 mph and his curveball has been more unhittable, leading to a 0.61 ERA and 28 strikeouts in 14 2/3 innings.

8. Devin Williams, RHP, Brewers (graduated from Top 30)
Previous RPR: unranked
Williams battled injuries and inconsistency in his first six seasons as a pro before breaking out in 2019, thanks to a mid-90s fastball and a dancing changeup that he uses more than his heater. Hitters have gone 0-for-27 with 18 strikeouts against his changeup this year, and his overall numbers (0.73 ERA, .093 opponent average, 25 strikeouts in 12 1/3 innings) are also outstanding.

9. Jesús Luzardo, LHP, Athletics (No. 1/MLB No. 13)
Previous RPR: unranked
One of the best pitching prospects in baseball, Luzardo has been the most effective rotation piece for the AL West-leading Athletics, who have won four of his five starts. He sports a 3.74 ERA in seven outings, including 34 strikeouts in 33 2/3 innings.

10. Matt Foster, RHP, White Sox (No. 28)
Previous RPR: 5
A 20th-round pick in 2016, Foster never has been highly touted and didn't make Chicago's Opening Day roster, but he has been terrific since promoted on July 29. He has permitted a run in just one of his 11 appearances, logging a 1.20 ERA and .122 opponent average with 18 strikeouts in 15 innings.