CLEARWATER, FLA. - Scott Baker's throwing elbow has become a concern for the Twins again.

Baker would have pitched Thursday, when the Pirates come to Fort Myers, Fla., but his inability to get loose in a B game against Pittsburgh last Saturday raised some red flags.

Baker's fastball, which normally averages 91 miles per hour, was clocked between 83-86 mph in that outing, and he gave up six runs on six hits in 11/3 innings.

Baker, 30, made two trips to the disabled list last year because of a strained right flexor muscle and was limited to two starts after July 28.

Pitching coach Rick Anderson said he wants Baker to get through a bullpen session with no trouble before scheduling his next start. Baker told the staff his arm felt good during workouts Wednesday, but this is an issue the Twins will monitor daily.

Jim Thome, who signed a one-year, $1.25 million deal to return to the Phillies, played four innings at first base in a minor-league game Monday. This is notable because Thome hasn't played first base in a regular-season game since 2007.

"He didn't even have a glove when he was with us," Twins manager Ron Gardenhire said.

Unlike the Phillies, the Twins had the option of giving Thome at-bats at DH. He hit 37 of his 604 career home runs for Minnesota.

"We didn't mess around with the other stuff [defensively] because he had the back issues," Gardenhire said. "Over here [with the Phillies], it's probably a good thing."

Thome, 41, is noticeably thinner these days. He slimmed down this offseason knowing he'd be playing some first base, while Ryan Howard recovers from a ruptured Achilles' tendon.

Thome didn't play against the Twins on Wednesday, but he greeted several of his former teammates near the batting cage.

Asked if playing first base was like riding a bike, he said, "It's not like a bike -- no. I think the key for me is getting my body to react again to playing the field and being out there more than I have in the last six or seven years."

Gardenhire plans to have Justin Morneau bat cleanup, between Joe Mauer and Josh Willingham. Asked if he sees a scenario where the righthanded-hitting Willingham would move in between the lefthanded-hitting M&M Boys, Gardenhire said it might happen against tough lefthanded pitchers.

• Denard Span (stiff neck) returned to the lineup and went 3-for-4. Tsuyoshi Nishioka (strained pinkie) went 1-for-4 in his return.

• Brian Duensing pitched two innings in a minor-league game, allowing one run on two hits with one strikeout.

On deck

Terry Doyle, the Rule 5 draft pick who allowed seven hits over 22/3 innings Saturday against Pittsburgh, gets another start against the Pirates on Thursday. Jo-Jo Reyes is scheduled to start for Pittsburgh.

JOE CHRISTENSEN