It’s tough to get much attention when AL ERA leader Felix Hernandez is your teammate, but Hisashi Iwakuma is quietly emerging as a formidable sidekick at the top of the Mariners’ rotation.
Iwakuma gave up two runs over seven innings last night in a 6-3 win over the Athletics. The 32-year-old struck out nine and walked none while retiring 16 batters in a row at one point. Brooks Baseball notes that he had 12 swings and misses, including five on his splitter, which has emerged as a legitimate weapon during his brief time in the majors.
Just to give you a sense of how good Iwakuma has been this season, his ERA actually went up from 1.61 to 1.74 with last night’s start. Still, he hasn’t allowed more than three runs in any of his eight starts this season and owns a stingy 51/8 K/BB ratio over 51 2/3 innings. His 0.74 WHIP is the best in the American League. And to think, he has pitched most of the season with a blister on the middle finger of his throwing hand.
Iwakuma’s dominance actually dates back to last season, as he has a 2.33 ERA in 24 starts since moving to the rotation last July. Only Justin Verlander, Clayton Kershaw, Matt Harvey, and Kris Medlen have a lower ERA in the same timespan. It’s unlikely that he’ll be able to maintain his .198 batting average on balls in play (BABIP) and 84.4 percent strand rate, so some regression should be expected, but the Mariners’ decision to keep him around on a two-year, $14 million deal looks pretty smart right now.