1) Clay Buchholz
Despite some recent collarbone issues, Buchholz has cemented himself as one of the top hurlers in all of baseball. The Red Sox ace has an AL-best 1.73 earned-run average (the only ERA under 2.00 in the league) and a 2nd-best (T) 7 wins, as well as top 10 numbers in strikeouts and WHIP. In all ten of his starts, the Red Sox have won all but one game (they were held scoreless until the 8th inning). Buchholz has also had quality starts in 9 of 10 appearances–that one outlier was the also the only contest in which he didn’t reach at least 7 innings.
2) Matt Moore
Moore leads the American League with 8 victories, whose 2.21 ERA stands second only to Buchholz. Like the Red Sox pitcher, Moore’s team–the Rays–thrive off his performances, losing in just one of his starts (he went 6 innings and yielded 1 ER). The Tampa Bay ace doesn’t turn to K’s for outs like so many of his top-notch counterparts, but similar to them, has still had great success: 9 of his 10 starts were quality and in each he hit the triple-digit pitch count. Moore’s one flaw is that he only averages slightly over 6 innings per start (with 3 outings under his average)
3) Yu Darvish
Darvish has all but mastered the popular art of the strikeout, and has led his Rangers–who many counted out in the preseason–to form possession of the AL East. Yet while his 2nd most (T) AL wins (7) and most strikeouts in all of baseball (105) bode well for the slinger, another category he leads may not be so auspicious: he has the most pitches thrown in all of the majors, which could deteriorate his health.
4) Max Scherzer
With Justin Verlander struggling in the early part of the year, the Tigers’ other star pitcher–Scherzer–has taken control of the Detroit rotation. With a 2nd-best win total in the AL (7), Scherzer also stands tied for 3rd in strikeouts (81) and holds a very impressive 3rd-best WHIP (0.92), especially considering his erratic pitching past. Yet there is still some cause for concern for the developing hurler: Scherzer still posts a mediocre 3.42 ERA, and his AL 2nd-best run support (6.70) makes up for his 4 non-quality starts
5) Hisashi Iwakuma
One of the early surprises of the 2013 season, Iwakuma barely edges out his fellow rotation teammate King Felix to round out the top 5. The Mariner has a AL 3rd-best 2.35 ERA, along with the best WHIP in the league which stands at 0.84. Though he only has 5 wins (partly due to poor run support), Iwakuma has quality starts in all but 1 of his total 10 outings.