Peterson (0-4) took the loss Wednesday against the Nationals, allowing seven runs on five hits and three walks in 3.2 innings. He struck out five.
Peterson entered in long relief in his prior two outings, but he didn't fare well in his return to the rotation. The left-hander coughed up a season-worst seven runs Wednesday, walking multiple batters for the fifth time in as many starts on the year. Peterson has a ghastly 6.53 ERA, 1.71 WHIP and 29:14 K:BB over 30.1 innings, so he'll be tough to trust in fantasy lineups during his next scheduled outing in Colorado.