"The Nationals officially introduced left-handed pitcher Scott Olsen and outfielder Josh Willingham at a Tuesday press conference at Nationals Park. The two players arrived via Monday night's trade that sent second baseman Emilio Bonifacio and minor-leaguers P.J. Dean, a right-handed pitcher, and Jake Smolinski, a second baseman, to the Florida Marlins.

"These guys are still very young and we control [their rights] for three more years," said Nats general manager Jim Bowden. "This is not a trade where we are renting a player for a year. These are two players that can fit in a long-term plan here."

The trade was actually agreed to last Wednesday at the General Manager's meetings in Dana Point, Calif. But because of the injury histories of both Willingham (bulging disc in back) and Smolinski (torn ACL and MCL last month) each team needed time to complete medical evaluations.

The 6-foot-5 Olsen gives the Nats a rotation workhorse. He pitched a career-best 201 2/3 innings last season and turns 25 on Jan. 12. His biggest improvement last season - when he posted a 4.20 ERA in 33 starts - was the addition of a change-up to go with his fastball and slider. It's a pitch that is admittedly a work in progress, but provides hope Olsen hasn't yet reached his potential.

"I hope there's another level. I would like to think you're never satisfied with the year," Olsen said. "As a pitcher you pretty much aren't going to go 33-0 so there's always room for improvement."

One concern about Olsen is a series of off-the-field incidents in recent years, including a DUI arrest in 2007 and multiple confrontations with Marlins teammates. Olsen was suspended two games for insubordination after a physical altercation with fellow pitcher Sergio Mitre during a game against the Nats on July 15, 2007.

"I just knew something had to change," Olsen said. "It just started off slow and you just try to keep yourself out of situations where there might be a problem. I think that's the biggest thing with all this maturing that everybody claims I've done."

Willingham, 29, was acquired strictly as a corner outfielder, according to Bowden, and not to replace often-injured first baseman Nick Johnson. Willingham has had a herniated disc for several years, according to Nats medical director Wiemi Douoguih. That injury flared up last April and cost Willingham two months. But he returned before the All-Star break and reported no further problems.

"The back has been good since I came back in late June," Willingham said. "I was healthy, it just took me a little while to get going. You never know what's going to happen. But I'm a lot more comfortable managing myself.""