PITTSBURGH -- The Jason Bay of 2008 is looking a lot like the Jason Bay of 2005 and 2006, which bares little resemblance to the Jason Bay of 2007.

Bay, who posted a two-season run as one of the most productive offensive players in Major League Baseball two and three years ago, regressed last season. But buoyed by a scorching fortnight and a strong May overall, Bay is reminding people how good he can be.

"Is it Old Jason? Whatever, it's [the real] Jason Bay," Pirates manager John Russell said. "He's swinging the bat very well. He's a threat at the plate and comes up with big hits for us."

Bay hit .306 with a.559 slugging percentage, 32 home runs and 101 RBIs in 2005, and batted .286 with a .532 slugging percentage, 35 home runs and 109 RBIs in 2006. But last season (.247/.418/21/84) was the worst of his young career.

This season, the 2004 National League Rookie of the Year is back to his old ways, batting .287 with a .517 slugging percentage, 12 home runs and 25 RBIs in 171 at-bats.

"He's been coming through a lot lately, and that's what he's capable of doing," Russell said. "It's nice to see him feeling really comfortable. He really likes the way he's feeling physically and that's really helping him mentally."

Bay has been red-hot in recent weeks after a .253 average through April. He was hitting .329 with a .440 on-base percentage, .658 slugging percentage and six home runs in May heading into Sunday's game against the Chicago Cubs.

In particular, Bay had homered in five of his past nine games before Sunday, and had reached base safely in nine consecutive contests, and in 11 of 12.

"I am very streaky, and this is one of the times where, even when I haven't been hitting the ball, I still have been seeing it, which is a positive," Bay said.

Bay has been scorching at PNC Park this season. He's hitting only .215 with three home runs on the road but was batting .348 with nine home runs in his 25 games at home.

Those totals are counter-intuitive for a right-handed batter because PNC Park's power alley in left-center is the deepest part of the park, and the right-field porch is conducive to home runs.

Indeed, entering this season, Bay had hit 72 of his 117 home runs as a Pirate away from PNC.

"I think playing here for a few years, he knows the park," Russell said. "He's comfortable here. He knows if he hits the ball well, it's going to go out no matter what park he's at. He's played here long enough now to know that balls he hits here are going to go out. He goes to right-center very well, which is nice in this ballpark. I think it's just a comfort level he's at because he knows the park well and has played here a lot."

Bay homered Saturday and had the winning RBI single in the 14th inning later in the night. It was his first RBI single of the season and the first walk-off RBI of his career.