What happened: The ranking limits each club to one player and uses statistics through Tuesday. Clay Holmes, Liam Hicks, Tarik Skubal and Luis García Jr. fill spots 2-5; Jo Adell, Brett Bateman, Erik Miller, Robbie Ray and Connor Norby complete the list.
Why it matters: Mahle has stabilized an injury-hit rotation for the NL East leaders. Hicks is contributing to the American League's top club, while Ray is pitching for an NL wild-card contender.
By the numbers: Holmes allowed one run over his past 25 innings. Hicks produced a .328/.425/.522 line through 80 plate appearances, while García hit five homers with a .511 slugging percentage in his first 25 Yankees games.
What to watch: September results will show which additions retain prominent roles during the postseason races.