In 10 minutes surfing
www.retrosheet.org,
Billy Wagner, who had a career ERA of 2.31 and in every season but one posted an ERA of 2.85 or lower.
His 2000 season: 46 baserunners allowed and a 6.18 ERA in 27.2 innings.
Rollie Fingers from April 22 through May 11 1979: 18.2 IP, 23 hits, 8 walks, 14 runs.
Rollie Fingers from July 26 through August 12 1979: 7 G, 8.1 IP, 15 hits, 8 walks, 17 runs
Roger Clemens from June 1 through July 16 1987 (a year in which he won the Cy Young award): 10 G, 75 IP, 71 hits, 29 walks, 8 HRA, 43 runs allowed. Gave up 7 runs twice, 8 runs once, 6 runs once...if he hadn't thrown a shutout against the hapless Indians in that stretch he would look even worse.