The Phillies bullpen was outstanding early in the year, but they’ve been a little less outstanding lately. The numbers for the season overall are still good, the 3.49 ERA the pen has thrown to this year is sixth-best in the NL, but the pen has fallen off overall.

Here’s what the relievers for the Phils did in April and May and what they have done since:

IP/G ERA Ratio K/9
April and May 2.75 2.80 1.28 6.9
June, July & August 2.35 4.09 1.27 8.4
Total 2.54 3.49 1.27 7.7

Since the end of May, the pen has been throwing fewer innings per game and striking out more batters when they do pitch, but with worse results overall. In their appearances in April and May, Phillie relievers allowed about 0.34 runs per inning pitched. In their appearances since the end of May they have allowed about 0.47 runs per inning pitched.

The bullpen is still throwing a tiny number of innings compared to the rest of the league. No NL team has thrown fewer frames than the 322 2/3 innings the Phils have tossed this year — the Dodgers are 15th in the NL in relief innings pitched and LA relievers have thrown 18 more innings than the relievers for the Phillies have.

In this post from January, I pointed out that in 2010 the Phillies relievers threw not just the fewest number of innings in the NL, but the fewest number of innings that any NL team had thrown for five years. At this point in the 2011 season, the Phillies have played 128 games and thrown 322 2/3 innings, which puts them on a pace to throw about 408 1/3 innings for the year. That would be fewer than the 421 innings they threw during the 2010 season, but still more than the 397 2/3 innings that the St Louis bullpen tossed during the 2005 season.

The strong start to the year makes the numbers for the Phillies pen look pretty good overall compared to the rest of the league. But the relievers have thrown to a 4.09 ERA since the end of May and that’s a whole lot less exciting than the 2.80 ERA for the first two months of the year. Only two NL teams, the Mets and the Astros, have seen their relievers throw to an ERA worse than 4.09 for this season overall.

Oswalt (6-7, 3.51) faces righty Clay Hensley (1-5, 5.47) tonight as the Phils start a series with the Marlins. Right-handed hitters have hammered the righty Hensley this year, hitting .337 against him. Hensley was a reliever in the first half of the season and threw to a 3.60 ERA over 15 appearances. Since the All-Star break he has appeared only as a starter, starting seven games and throwing to a 6.29 ERA. His first three starts after the break were good — he threw to a 2.65 ERA and opponents hit .165 against him. Over his last four starts he has allowed 19 runs in 17 1/3 innings. Oswalt was fantastic his last time out, throwing eight shutout innings against the Nats and striking out nine. He has been hit hard by righties this year, they have posted a 305/346/447 line against him, which is way better than their 247/295/384 line against him over his career.

Sunday’s game has been moved and will be played as part of a double-header on Saturday.