MINNEAPOLIS -- Twins catcher Joe Mauer is eligible to return from the 60-day disabled list on Sunday, but will need to catch multiple days in a row before he's activated from the disabled list, Twins manager Ron Gardenhire said on Thursday.
The Twins initially targeted Sunday as a possible return date for Mauer -- who is slated to catch on Thursday night with Class A Fort Myers after catching eight innings on Wednesday -- but he likely won't join the team until late next week at the earliest.
"We talked about after the 12th when he came off the 60-day DL, if he was ready, then we'll bring him up here," Gardenhire said. "If he hasn't caught enough and we don't deem ready to do that, we won't do that. We saw that happen in Spring Training when we thought he was ready."
Mauer could also see time with Triple-A Rochester to see better pitching, but at this point the club is more worried about Mauer getting time behind the plate than anything else.
"My concern more for Joe than Triple-A is being able to catch back-to-back-to back games," Gardenhire said. "I think he's caught 22 innings up to this point, and I don't think that's enough catching to say he's ready to start the grind up here of catching four or five games in a row."
Mauer has played only nine games with the Twins this year and last played on April 12, when he caught 10 innings against the Royals.
"He's anxious to get up here and wants to play," Gardenhire said. "He's missed a lot of baseball games. But on the flipside of that, we have to make sure he's ready to get back up here and catch three or four days in a row."
Span placed on seven-day DL with concussion
MINNEAPOLIS -- After meeting with team doctors and a specialist on Thursday, center fielder Denard Span was placed on the seven-day disabled list with a concussion.
Outfielder Rene Tosoni was recalled from Triple-A Rochester and will join the Twins before Friday's game against the Rangers.
Span suffered the concussion last Friday during a home-plate collision with Royals catcher Brayan Pena, and has been dealing with head and neck issues ever since. He said he was feeling better on Thursday, but there were still some lingering effects.
"I feel better than I did [Wednesday], just taking one day at a time," Span said. "My neck's still a little bit sore, and I still get dizzy here and there."
After flying back from Cleveland to Minnesota on Tuesday night because of the headaches, dizziness and a stiff neck, Span saw a specialist at a balance and dizziness center.
Span spent four hours going through a number of tests on Thursday.
"All different types of tests, letting them spin me around in chairs and throwing on goggles and all this crazy stuff," Span said. "They wore me out today."
Span said the symptoms are similar to the vestibular neuritis he dealt with in 2009, and that those symptoms have never fully gone away. Doctors told Span that some of the symptoms he had in 2009 had flared up again after being triggered by the concussion last week.
Over the last couple days, Span said he would occasionally feel "spaced out," or like the "room was moving a little bit."
"It's not all the time, it just comes and goes," he said. "There have been times when I'm at home relaxing and it comes, and sometimes I'm relaxing and I don't feel it. I think little things, like maybe bright lights every now and then or if I've got a lot of people around me like now, I start to feel a little funny."
The seven-day DL was implemented this season to give teams more options when dealing with concussions.
With so many other players already injured already this season, it helps the Twins bring up an extra outfielder without having to sideline Span any longer than necessary.
"If I'm healthy in seven days I come off, if I'm healthy in eight days, I come off," Span said. "There's a lot more flexibility for the player to come back. With a concussion everybody heals different and you just never know. I could feel better tomorrow. You just never know."
Gardy in no hurry to end Nishioka's rehab
MINNEAPOLIS -- Tsuyoshi Nishioka could be ready to return as soon as early next week, but Twins manager Ron Gardenhire wants him to play at Triple-A Rochester first.
After playing nine innings on Wednesday night for the Miracle, Nishioka was scheduled to play nine innings at shortstop for Class A Fort Myers again on Thursday. Batting leadoff, Nishioka went 1-for-3 with a double and a run scored while also striking out twice.
Nishioka was eligible to return from the 60-day disabled list on Tuesday, but Gardenhire has no problem giving him a few more days on his rehab assignment before he returns.
"I don't want him rushed up here," Gardenhire said. "He's not been swinging great, so I want to see him go full out. My preference is for him to go to Triple-A and play whatever, three, four more ball games. Just to see how he's handling himself and make sure he's on track, make sure he's ready to step in and play right up here."
Thome may resume activities this weekend
MINNEAPOLIS -- Jim Thome's quadriceps injury is related to his previous oblique injury, Twins head trainer Rick McWane said on Thursday.
After undergoing an MRI on his quad, back and hip, it was determined the pain in Thome's quad was being caused by his back.
"We've consulted with our back specialists and some other ones," McWane said. "The best course of action is [Friday] [Thome] is going to have an epidural in his back, and that should take care of the symptoms he's having in his quad."
If the treatment works, Thome's baseball activities will progress this weekend.
First baseman Justin Morneau also underwent an MRI on his wrist, which showed some fluid, but no structural damage. McWane said the Twins would let Morneau continue to play as tolerated.
Twins reliever Joe Nathan (elbow soreness) threw a bullpen session on Thursday that went "great," McWane said. Nathan is scheduled to throw another bullpen session on Saturday.
"If it goes well on Saturday, he'll also go to Fort Myers [Fla.], probably Sunday," McWane said.
Kevin Slowey (abdominal strain) continued to progress as well, throwing long toss on Thursday up to 120 feet with no complaints.
On the 15-day disabled list with a left foot sprain, Jason Kubel hit in the cage on Thursday and did some agility drills. McWane said Kubel felt "OK," and that they would progress his baseball activities through the weekend.
Lefty reliever Glen Perkins (strained right oblique) threw a bullpen session on Thursday and is scheduled for a rehab stint with Triple-A Rochester beginning this weekend.
"[Perkins] is headed to Toledo tomorrow," McWane said. "He's going to pitch an inning on Saturday."
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.