BOSTON - The Twins widespread injury concerns now include shortstop Trevor Plouffe.

The rookie is questionable for Monday's series finale after leaving Sunday's game because of an injured left hamstring. He said it felt like a cramp as he rounded the bases, but the soreness lingered after the game.

"See how it feels tomorrow," Plouffe said. "If it's up to me, I'm playing."

Earlier in the Twins' 9-5 loss, Boston's Jacoby Ellsbury spiked Plouffe in the right knee while getting tagged out at second base. Plouffe, 24, was in obvious pain and had a nasty wound but played four more innings.

Manager Ron Gardenhire wants to give Plouffe an extended look, as the Twins try to decide whether to bring Tsuyoshi Nishioka back as a shortstop or a second baseman when he returns from the disabled list.

Plouffe is 3-for-10 with a home run and a double. He has been on base six times in three games. Defensively, he has yet to be charged with an error but has missed two makeable plays that were ruled hits.

Nishioka update The Twins sent special assistant Paul Molitor to Fort Myers, Fla., to work with Nishioka on his double play technique as a second baseman.

Gardenhire said Nishioka can improve his footwork around the base to help prevent future injuries. Nishioka broke his left fibula on April 7, when the Yankees' Nick Swisher made an aggressive takeout slide into second base.

Nishioka will have another X-ray this week before being cleared to play in minor league games. Gardenhire said the reports say Nishioka still has soreness when he fields ground balls.

"The big thing for me, is I do not want to see him out there in any kind of contact until we make sure the leg is healed," Gardenhire said. "Because I can tell with Nishi -- he wants to go, and he'll play with pain. I just don't want to make this linger into a longer thing."

Training room tidbits • Delmon Young (strained oblique) headed to Fort Myers, and could be ready to begin playing in minor league games by Tuesday, Twins assistant trainer Dave Pruemer said. Young, who led the Twins with 121 RBI last year, isn't expected to need a long rehab stint.

• Jim Thome's MRI exam showed a small strain in a back muscle. "Nothing real major," Pruemer said, "so he'll start rehabbing and should be fine."

• Joe Mauer (bilateral leg weakness) continues to hit and throw daily at Target Field and is getting stronger, Pruemer said. But there's still no timetable for Mauer's return.

• Jose Mijares, who was sick Saturday and sent home to the team hotel, felt better Sunday but gave up two runs (both unearned) on two hits in the seventh inning.

Valencia delivers Before Sunday's game, Gardenhire said, "The guys we have out there in the clubhouse have to get it done until the guys come back. That's the bottom line."

Gardenhire specifically mentioned Jason Kubel, Justin Morneau, Michael Cuddyer and Danny Valencia.

"Kubel's swinging good, Mournie's OK, Cuddy's gotta get driving the ball, and Danny Valencia too," Gardenhire said.

Valencia responded, going 2-for-4 with a two-out, two-run single in the first inning and a home run in the fourth off Daisuke Matsuzaka. Kubel went 3-for-4 with two RBI, raising his average to .351, but Morneau and Cuddyer combined to go 0-for-8.