ARLINGTON, TEXAS - Matt Tolbert, Trevor Plouffe and Luke Hughes will man second base for the injured Alexi Casilla.

Casilla strained his right hamstring while running out a double in the ninth inning on Wednesday during the Twins' 7-2 win over the Rangers. An MRI exam on Thursday determined that the strain is between a Grade 1 and 2 (Grade 3 is the worst).

Casilla hoped to not be out long, but the Twins estimate he will miss two to three weeks.

"They preferred to put me on the DL so I can take it easy and take care of the hamstring," said Casilla, who flew back to the Twin Cities on Thursday afternoon to begin rehabilitation.

Tolbert was called up Thursday morning and made it to the park in time to start at second base. He batted .194 in 10 games with Rochester with a double, triple and three RBI. He entered Thursday batting .181 in 47 games with the Twins.

Plouffe offers more offensive potential than Tolbert but not better defense. He is batting just .207 but has five home runs and 14 RBI. Plouffe hit .313 with 15 homers at Rochester.

One issue is that Twins manager Ron Gardenhire hasn't seen Plouffe play much at second base and has to become comfortable with him there.

"He will definitely take ground balls there," Gardenhire said.

Hughes will join the club Friday after being called up from Rochester. He was sent down July 22 and the rule is that a player must stay down at least 10 days before he can be called back up -- unless there's an injury.

Gardenhire will go with the best matchup of the day at second base until Casilla is ready. It's a blow to the Twins because Casilla has been playing well defensively, and his double Wednesday moved him into the team lead with 21.

"That's a hole we have to fill again," Gardenhire said. "Ad-lib again. What are you going to do?"

Span update

Players on the disabled list can be traded, so that won't be a hurdle if the Twins do decide to move outfielder Denard Span.

Span is wanted by Washington, but the Twins won't move him unless they get an offer they can't refuse.

Span (concussion) was back in the lineup for Class AAA Rochester on Thursday after playing into the 10th inning on Wednesday. He doubled in the 10th and was replaced by a pinch runner. If Span can play nine innings in three consecutive games, he could return to the team by the end of the weekend.

"He continues to do well," Twins trainer Rick McWane said. "No concussion symptoms."


• First baseman Justin Morneau (neck surgery) felt better Thursday after battling migraines for a few days.

• Lefthander Corey Williams, the Twins' third-round pick in the June draft, has reported to rookie league team Elizabethton after signing for $575,000 -- which is more than double the league-recommended bonus for that spot. The Twins have made good progress with their first-round pick, shortstop Levi Michael, and hope to have a deal wrapped up soon.