DETROIT -- The Tigers raised some eyebrows around baseball when they re-signed Sean Casey to a one-year, $4 million contract during the offseason.

Some skepticism was understandable. Casey, who will be 33 years old in July, had been slowed by a torn calf muscle last season and had seen his batting average drop each of the last three years, from .324 to 2004 to .312 in 2005 to .272 last year with Pittsburgh and the Tigers. His on-base percentage has been on a similar track, from .381 to '04, to .371 the following year and .272 last season.

Casey doesn't have much power (126 homers in 4,545 career at-bats entering Sunday's game against St. Louis), and since hitting 24 three years ago for Cincinnati, Casey has hit nine and eight homers, respectively, the last two years. Casey is a good fielder but doesn't have much speed.

What Casey is, besides being one of the best ambassadors the sport has to offer, is a left-handed-batting line drive hitter who gets on base and doesn't strike out very often. Which makes him a perfect complement to Detroit's predominantly right-handed-hitting lineup and spacious Comerica Park.

Or so he is when he's hitting. But Casey's three-year slide continued in April when he batted just .192.

Skeptics would say they told you so. The Tigers, however, saw value where others saw reasons to pass on Casey, and the bet here is Casey will once again reward the franchise as he did last fall, when the first baseman batted .432 in the playoffs including .529 in the World Series.

"He's still a good hitter, puts the ball in play," Tigers manager Jim Leyland said. "Obviously he hasn't had as much success up to this point, but we need Casey to put the ball in play and knock in a few runs -- there's no question about it. He's struggled to start the season, but this is a long haul."

Casey has already shown signs he is breaking out of his slump and beginning to hit at something closer to his .301 career batting average.

He went 6-for-9 with two RBIs in the first two games of the series against St. Louis, continuing the torrid hitting against the Cardinals. Counting the last four games of the Fall Classic, Casey is batting .636 (14-for-22) in his last six games against the World Series champions.

Since the calendar turned to May, Casey is batting .340 (18-for-53) to raise his season average to .252. He's boosted his on-base percentage 109 points (to .368) and his slugging from .244 to .415.

All but forgotten in light of his fantastic October was a poor September during which Casey hit .209. Part of that was injury related, but for Casey, who had spent most of his decade in the Major Leagues in the National League, learning American League pitching was a learning process that he's still going through.

"For me the main thing is taking quality at-bats, making the pitcher work on each pitch and hitting my pitch and not [the pitcher's]," Casey said. "Over the course of a season, you're going to have ups and downs, and you have to make adjustments to how they're pitching you."

Casey knew if he kept working, in time he'd get back to where he should be. Like the old saying goes, cream rises to the top.

"I know one RBI [in a month] isn't going to get it done," Casey said. "And I never believed I was going to stay at that (.200) level."

Casey has driven in seven runs so far in May, and has reached base in all but six of his last 17 games. Even when opposing pitchers are getting him out, Casey has more often been hitting the ball hard in recent weeks.

"He's using all fields and hitting the ball hard," Leyland said. "I've seen a lot of good things from him offensively, especially the last two, three weeks or so."

Getting Casey back at the bat is pivotal for the Tigers. As one of three left-handed bats in the regular lineup, along with Curtis Granderson and switch-hitting shortstop Carlos Guillen, Casey gives Leyland more game strategy choices. More power would be welcomed, but with Gary Sheffield and Magglio Ordonez, the main thing the Tigers need from Casey is for him to hit. Just hit, and the rest should fall into place.

"These things never turn around as fast as you'd like," Casey said. "But it's still early."

Plenty of time for Casey to find his groove and figure out the American League pitching a little better.

"I'm sure there's a comfort zone," Leyland said. "[He's] got a better feel [and he's] been a smart hitter all his life."

And like the man said, it's still early.