Peterson (0-2) was tagged with the loss Wednesday against the Diamondbacks after allowing five runs on six hits and two walks across five innings. He struck out six.
Peterson opened the season with 5.1 scoreless innings against the Pirates on March 28, but the wheels have fallen off completely in the last two starts. He's given up 11 runs (10 earned) on 15 hits and four walks while striking out 11 across 9.1 innings. It's too early to say if his spot in the rotation is at risk, but the left-hander naturally can't afford many more stumbles. Peterson's next start won't be any easier, as he's tentatively lined up to face the Dodgers on the road next week.