ST. LOUIS -- The Cardinals addressed two problems with one move on Friday, allowing a torrid hitter to taste the big leagues while simultaneously allowing a scuffling player to play every day in hopes of getting sorted out.

Outfielder Joe Mather, who had been abusing Pacific Coast League pitching, was recalled from Triple-A Memphis and inserted immediately into St. Louis' lineup against the Pirates. Outfielder Chris Duncan, who has been searching for his power stroke for more than 10 months, was optioned to Memphis.

"We try to look at it in terms of what's best for the organization, but also what's best for the player," said Cardinals general manager John Mozeliak. "And we just felt like that was the answer. I'm sure there are some people who will disagree, and will find some holes in it, but we thought it was the right thing to do. Time will tell."

Duncan simply hasn't been the same hitter since he first sustained a hernia around the midpoint of last season. From his Major League debut in 2005 through the end of July last year, Duncan hit .289 with a .574 slugging percentage and 43 home runs in 575 at-bats. Since then, he has hit .217, slugged .323 and hit five homers in 217 at-bats.

Mozeliak and manager Tony La Russa said they are convinced that Duncan has recovered fully from the injury, for which he had surgery last year. But it's clear that his swing has not recovered. That, combined with a string of left-handed opposing starters in the coming days, added up to a move.

"I think it's more a matter of just tweaking his stance and concentration and all that stuff -- stuff that you need to play to fix," La Russa said. "Because I watch him in the cage, and when it all clicks, the ball is doing all the good things."

In Duncan's replacement, the Cardinals call up a player who has more than earned a chance to play in the Majors. Mather, 25, enjoyed a breakout season at Double-A Springfield last year and has followed it up by dominating the PCL thus far in 2008. He's batting .315 with a .406 on-base percentage and .671 slugging percentage at Memphis, with 12 home runs in 143 at-bats.

That followed a long stretch when it was unclear whether Mather would ever see the high Minors, never mind the Major Leagues. He was in his fourth professional season before he played full-season ball, and in his seventh season before he reached Double-A.

"I guess I just told myself I could do it enough," Mather said. "I never really gave up on myself. There were some times when I was hitting under .200 in A-ball, and that's not going to cut it. I guess I didn't give up on myself and kept working, and it's turned out how it has."