The Orioles have placed 29-year old righty reliever Alfredo Simon on the 15-day disabled list with a left hamstring strain. Simon has pitched in 12 games (0 starts) for the Orioles so far this year and he was 1-1 with 6 saves, a 2.92 ERA and a 1.54 WHIP. Simon will be replaced as the closer by 32-year old lefty Will Ohman. Ohman has pitched in 24 games (0 starts) for the O’s this year and he is 0-0 with a 0.00 ERA and a 1.23 WHIP. He has whiffed 15 batters while only allowing 10 hits in 14 2/3 innings this season showing that his stuff is probably good enough to handle the job if he can get righty hitters out. But he has walked 8 batters this year and he will need to tighten his control if he is to have success as a closer. The O’s have recalled 26-year old righty reliever Frank Mata to replace Simon in the bullpen. Mata has pitched in 18 games (0 starts) in AAA-ball this year and he is 2-1 with 8 saves, a 1.86 ERA and a 1.14 WHIP. He has now pitched in 216 games (6 starts) in his six years in the minors and he is 15-16 with 33 saves, a 4.08 ERA and a 1.44 WHIP.