Those stats were not even for a full 9 innings of pitching. He only had to get rocked in 1 game for his stats to blow up.
Melancon pitched in 7 games against the AL in 2011.
He was fine in his first two games in May against Toronto.
After that, he proceeded to give up runs all but one of his next 5 games against the AL, the one game he didn't give up runs he only pitched to one batter against Texas.
The other games;
Texas - 1 inning, 2 hits, 1 HR, 1 run
Texas - 2 innings, 1 hit, 3 walks, 1 run
Tampa - 1.1 innings, 6 hits, 1 walk, 1 HR, 5 runs
Boston - 1 inning, 1 hit, 3 walks, 1 run
Over those 4 appearances, his ERA was 13.50
Very small sample size, but of the 23 earned runs he gave up last year, 35% came in those 4 games. Those teams were #1, #2, and #7 in batting in 2011. The one team that didn't score against him was the Jays down at #16.
Make of it what you will