MINNEAPOLIS -- Twins first baseman Justin Morneau, who underwent surgery to remove a herniated disk fragment in his neck on June 29, could rejoin the club as early as Monday, in the opener of a three-game series in Detroit.
He played in his fifth rehab game with Triple-A Rochester on Tuesday, going 3-for-5 with two doubles and an RBI, while playing nine innings at first base. He's hitting .409 with four doubles and five RBIs with the Red Wings.
"He's hitting the ball hard," Minnesota manager Ron Gardenhire said. "He's getting some swings in. We'll go day by day and see where he's at. So probably Detroit or something like that. We'll see how it goes."
Morneau was originally placed on the disabled list, retroactive to June 10, with a sprained left wrist, before electing to undergo neck surgery later in the month. He was hitting .225 with four homers and 21 RBIs in 55 games before hitting the DL.
Second baseman Alexi Casilla, who is on the disabled list with a strained right hamstring suffered on July 27, ran the bases aggressively on Tuesday, and remains on track to be activated on Friday in Cleveland.
"He did really good running. He had no problems and said he could play today if were available. So he'll run again tomorrow, and is doing all his work. We plan on activating him on Friday."
Struggling Span gets breather in middle game
MINNEAPOLIS -- Twins center fielder Denard Span got the night off Tuesday, his second since coming off the disabled list last week.
Span has struggled in six games since his return, picking up just one hit in 24 at-bats for a .042 average, with one run scored, seven strikeouts and a walk.
Twins manager Ron Gardenhire said Span is still working on getting back to 100 percent after missing two months due to a concussion suffered in a home plate collision against the Royals.
"He still has his moments," Gardenhire said. "So, just back him off here and there. I talk to him daily, and today was a good day."
Span was available Tuesday off the bench if needed. As for Span's struggles since coming back, Gardenhire said he's still working on getting his timing down after not seeing big league pitching for two months.
"Seeing the ball, we talked about not really seeing the spin real good yet, and picking up the ball and all those things," Gardenhire said. "So we'll back him off a day, we'll see how he is tomorrow and go from there."
In Span's place, Ben Revere got the start in center field.
Prospect Gibson has elbow strain, ligament tear
MINNEAPOLIS -- Twins top pitching prospect Kyle Gibson was diagnosed with a flexor pronator muscle strain of the right elbow and a partial tear of the ulnar collateral ligament, and will head to Fort Myers, Fla. this week to begin strengthening and flexibility exercises of the right shoulder and elbow, according to general manager Bill Smith.
Gibson is expected to avoid Tommy John surgery for now, as the estimated return for him will be determined after the initial phase of his rehab program.
"There's still a probably a few more hurdles to climb," Twins manager Ron Gardenhire said. "He's going to back off and wait for a while. But we'll see how he responds and go from there. That's all we can do now."
Fellow Triple-A Rochester right-hander Anthony Slama was also diagnosed with a flexor pronator muscle strain of the right elbow, and will head to Florida to begin his rehab process along with Gibson.
Both pitchers underwent MRIs last week and met with team orthopedists, Dr. Dan Buss and Dr. John Steubs, on Monday, before undergoing further testing on Tuesday.
Gibson, 23, was originally placed on the Minor League disabled list with soreness in the flexor muscle area near his elbow and underwent an MRI on Wednesday. The 6-foot-5 right-hander is the 33rd-ranked prospect in baseball and No. 2 in the Twins' system, according to MLB.com.
Gibson, the club's first-round pick in the 2009 First-Year Player Draft, had been struggling recently, as he went 0-5 with a 6.47 ERA in eight starts over June and July. It came after he entered June with a 3.60 ERA and 59 strikeouts in 55 innings.
Slama, meanwhile, was placed on the Minor League disabled list on July 6 because of elbow soreness. The reliever posted a 2.92 ERA with 42 strikeouts in 37 innings with Triple-A Rochester before his injury.
The 26-year-old also tossed 2 1/3 scoreless innings with the Twins this year in a brief stint with the club from late May into early June.
Rhett Bollinger is a reporter for MLB.com. Read his blog, Bollinger Beat, and follow him on Twitter @RhettBollinger. Jordan Schelling is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.