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."