Jarrod Parker

The A's have called up right-hander Jarrod Parker, their top pitching prospect, and he'll start Wednesday in Oakland against the White Sox, MLB.com's Jane Lee reports.

The A's acquired Parker last December as part of the deal that sent Trevor Cahill to Arizona. Last season, Parker, who was coming off Tommy John surgery, he posted a 3.79 ERA and struck out 112 in 155.0 innings for Double-A Mobile and didn't give up a homer over his last 87.2 frames. This season at Triple-A Sacramento, Parker has a 2.18 ERA and 21 whiffs in 20.2 innings.

In Matt's most recent prospect-rankings hootenanny, Parker came out of the wash as the 28th-best prospect in all of baseball. That's with good reason: Parker boasts good breaking stuff, a heavy two-seamer, a changeup that's been improving, and, when healthy, a knack for keeping the ball on the ground.