BP: Can Pelfrey keep this up?

Mike Pelfrey's performance Sunday night was far from a masterpiece.

The Mets right-hander allowed eight of the 23 batters he faced to reach base, five on walks and three on hits, as he struggled to throw strikes and get ahead of hitters. Yet on a night when he failed to retire two-thirds of the Braves' hitters, Pelfrey showed why he is one of the biggest early-season surprises in the major leagues and kept Atlanta off the board. However, a closer look at his performance shows that Mets fans should temper their expectations a little bit.

Whereas he would often cave under pressure in the past, the big right-hander was able to bob and weave his way through five scoreless innings as the Mets blanked the Braves 1-0 in a game called due to rain in the sixth inning. It was certainly an adventuresome five innings for Pelfrey on Sunday. He needed to throw 106 pitches to get his 15 outs, an average of 21 pitchers per inning. Pelfrey survived, though, by holding the Braves hitless in three at-bats with runners in scoring position, two of which ended when Jason Heyward and Troy Glaus grounded into inning-ending double plays.

Pelfrey joined the Phillies' Roy Halladay, the Rockies' Ubaldo Jimenez and the Giants' Tim Lincecum as the major leagues' only four-game winners while lowering his ERA to a 0.69, which is the lowest in baseball. Not bad for a guy who was 10-12 with a 5.03 ERA in 31 starts last season and one of the many reasons the Mets finished 70-92.

The biggest key for Pelfrey this year has been his performance with men on base. Foes are just 1-for-15 with runners in scoring position so far, and their batting average on balls in play is .077 in those situations. Last year it was .325. Little wonder Pelfrey told reporters after Sunday's game, "I must be living right."

That .077 BABIP with runners in scoring position is unsustainable (league average BABIP is around .290), but there is still reason to be optimistic about Pelfrey's performance this year. He's incorporated a split-fingered fastball, and his strikeout rate sits at a career-best 6.6 per nine. More notable is that he has yet to give up a home run, and keeping the ball in the park has been the key to his success in the past. When he posted a 3.72 ERA in 2008, Pelfrey allowed just 0.5 homers per nine, which was fifth best in the NL.

Pelfrey is not as good as his 0.69 ERA indicates, but there is every reason to believe that the 26-year-old will be the workhorse he showed he could be in 2008, and maybe a little bit more.

John Perrotto is the editor in chief of Baseball Prospectus.