I know the team's not playing the way it's capable of playing. They've had a lot to deal with this year. I'm excited to go in there and do whatever I can to help them get back on track.
The trade came with St. Louis struggling at 32-37 and the Tigers tied for the AL Central lead. The Tigers will receive a player to be named for Maroth, who had an arm operation last year.
Maroth knew a deal was imminent with Rogers rejoining the rotation in Atlanta after recovering from a blood clot in his left shoulder.
"There's only so many spots," Maroth said. "This team is stacked with pitchers, which is a great situation to be in from an organizational standpoint."
The 29-year-old Maroth was 5-2 with a 5.06 ERA in 13 starts. While those numbers may not seem impressive, they should be a boost to St. Louis' battered rotation.
"I've talked a lot to the Tigers and I think he can help us," Cardinals manager Tony La Russa said. "I'm pleased we were aggressive and we made a move."
How desperate are the defending World Series champions for reliable starters? Anthony Reyes was set to go Friday night with an 0-8 record and 6.34 ERA. Kip Wells was 3-11 with a 6.75 ERA and got scratched from a scheduled appearance Tuesday just hours before the game. Earlier this week, the Cardinals signed Tomo Ohka to a minor-league contract; he was 2-5 with a 5.79 ERA when Toronto released him.
La Russa said Brad Thompson, who allowed one run in seven innings against the Royals on Tuesday, was available in the bullpen over the weekend.
"Mike is a young pitcher who we feel is only going to get stronger as he continues his recovery from last season's surgery," Cardinals general manager Walt Jocketty said. "He is an established starter who is going to provide us with innings and help take pressure off of our bullpen. We think the change in leagues will also benefit Mike."
Maroth will return briefly to Detroit to gather some belongings and is scheduled to start Monday in New York against the Mets.
"I know the team's not playing the way it's capable of playing. They've had a lot to deal with this year," he said. "I'm excited to go in there and do whatever I can to help them get back on track."
Maroth went 5-2 last year while missing more than half the season after surgery to remove bone chips in his left elbow. He was not on the Tigers' postseason roster, missing out on Detroit's five-game loss to the Cardinals in the World Series.
"It's the perfect scenario for Mike," Detroit manager Jim Leyland said. "He's going into the rotation for the world champions."
Maroth is 50-62 with a 4.81 ERA in the majors. He was 9-21 in 2003 on the Tigers team that nearly set a big-league record for losses and was a key member of the rotation the next two years. This season, he was squeezed out by Detroit's impressive pitching depth.
"I'm not happy with the way I've pitched to this point," Maroth said. "Even though I've won a few games, the offense is the reason for that. I need to be more consistent making pitches. I know I'm much better than what I've done so far."
Justin Verlander (8-2), Jeremy Bonderman (8-0) and Rogers are Detroit's top three starters. Andrew Miller, a 6-foot-6 lefty and only 22, has looked good in three starts since coming up from Double-A. Nate Robertson is set to come off the DL next week.
"We like Miller a lot," Tigers general manager Dave Dombrowksi said. "We're in a position where we have starting pitching depth."
The deal was the second of the week for Detroit, which swapped left-handers with Atlanta on Wednesday. Wil Ledezma, who was out of minor-league options, was sent to the Braves for Macay McBride.
McBride has an option left and could be sent down when Robertson is activated.
The St. Louis-Detroit trade was the first between the teams since June 7, 1996, when the Cardinals acquired outfielder Micah Franklin and minor-league pitcher Brian Maxcy for pitcher Tom Urbani and minor-league infielder Miguel Inunza.
The Cardinals will place left-hander Tyler Johnson on the 15-day disabled list because of shoulder tendinitis when Maroth reports to the team, with the move retroactive to Tuesday. Johnson was not one of the eight pitchers, including Wells, who was used in a 14-inning victory over the Royals on Wednesday.