Jupiter, Fla. - The Florida Marlins acquired left-hander Nate Robertson from the Detroit Tigers for left-hander Jay Voss on Tuesday.

The trade enables Robertson to start with the Marlins and assures left-hander Dontrelle Willis a spot in the Detroit rotation. Robertson started six games and also spent time in the bullpen for the Tigers last season, finishing 2-3 with a 5.44 ERA in 28 appearances.

Detroit manager Jim Leyland said Willis would take the No. 3 spot in the rotation. Leyland figured Robertson did not want to be a reliever with the Tigers.

"He probably would have not been a happy camper if it would have worked out that he was in the bullpen," Leyland said. "He's been nothing but a good soldier here over the years. We appreciate everything he's done for us. I think this is a great opportunity for him and it unclogs the issue for us a little bit."

Robertson joins a Florida rotation that includes right-handers Josh Johnson, Ricky Nolasco, Anibal Sanchez and Chris Volstad.

"He is a left-hander, which is something we didn't have in the rotation," Florida baseball operations president Larry Beinfest said "And he brings experience, which is something we're light on also."

Right-hander Clay Hensley, who had been expected to join the Florida rotation after a strong spring, will instead likely pitch out of the bullpen.

Detroit is sending Florida cash as part of the deal for Robertson, who is owed $10 million this year in the final season of a $21.25 million, three-year deal. The Tigers will pay nearly all of his salary.

Robertson has a 51-69 record and 4.92 ERA in 202 games over eight big league seasons.

The 22-year-old Voss split last season between Class-A Jupiter and Double-A Jacksonville for the Marlins. In 10 games with Jupiter, he compiled a 2.03 ERA and 10 strikeouts. He was 3-0 with a 2.97 ERA and 36 strikeouts in 30 appearances with Jacksonville.

Robertson pitched for the Marlins briefly in 2002 before being traded to Detroit for Mark Redman, who helped Florida win the 2003 World Series.

Cubs release Millar

The Chicago Cubs released Kevin Millar, giving their final roster spot to infielder Chad Tracy.

The 38-year-old Millar hit .242 in 18 games this spring. He batted .223 with seven home runs and 29 RBIs for Toronto last year. He has also played for Florida, Boston and Baltimore.

The 29-year-old Tracy made the opening day roster because he hits left-handed and has been a regular at third base.

After spending all of his career with Arizona, he joined the Cubs as a non-roster invitee. He is hitting .243 in 20 games.

The Cubs also sent outfielder Sam Fuld and infielder Micah Hoffpauir to Triple-A Iowa and sent catcher Chris Robinson to their minior league camp for reassignment.

Hernandez is O's 5th starter

David Hernandez was named the fifth starter in the Baltimore Orioles' rotation, a move that means 21-year-old Chris Tillman will be headed to the minor leagues.

Hernandez and Tillman both made their major league debuts last year with Baltimore. They were competing this spring to fill out the rotation behind Kevin Millwood, Jeremy Guthrie, Brad Bergesen and Brian Matusz.

Chapman headed to minors?

Cuban defector Aroldis Chapman will likely start the season in the Cincinnati Reds' farm system.

General manager Walt Jocketty said that the left-hander has adapted well during spring training - he just turned 22 and is learning English - but had his chances of making the team scuttled by a back injury that cost him a week.

"The injury set him back to the point where it's going to be tough for him to be ready to start the season as a (major league) starter," Jocketty said. "I think we needed the spring to figure out the best route for him. Even without the injury, we may have decided to send him someplace to get established first."