Glen Perkins throws a bullpen session every Tuesday and Friday. On other days, he tries long-toss drills and other exercises designed to get him off the disabled list and back into major league games.

But Perkins is a little frustrated these days. He's not making progress. He can't throw at 100 percent without his shoulder resisting.

"I've been banging my head against the wall," Perkins said Wednesday. "I'd like to be further along than I am, but that is the way it goes."

One of the reasons Perkins is back in the Twin Cities is to figure out why he's not improving. Dr. John Steubs, Twins director of medical services, has been in touch with specialist Dr. Neal ElAttrache, who repaired Perkins' torn labrum last June 23. The two hope to come up with a plan to help Perkins get over the hump.

"I think he's a little frustrated that the way the ball is coming out isn't a little faster," Twins manager Paul Molitor said. "There are going to be some conversations with our people as well as the medical staff to see what we can do and maybe kind of jump that a little bit because it seems like he's kind of leveled off.

"He feels good, it just hasn't changed a lot as far what he does with the ball."

Perkins said he is going to remain in the Twin Cities until he's ready to pitch in games. That depends on how quickly he can clear the latest hurdle in his comeback from surgery. He thought he would be ready to pitch by May, but that isn't happening.

"There's no need for me to go down to Florida until I'm ready to face hitters," Perkins said. "Hopefully it is sooner than later."

Sano appeal Friday

Major League Baseball on Friday will hear the appeal of Twins third baseman Miguel Sano's one-game suspension for his actions during a game against the Tigers on April 22.

Sano was suspended and fined an undisclosed amount when he appeared to throw a punch at Detroit catcher James McCann. Sano has claimed it was a shove. The incident began when Detroit lefthander Matt Boyd threw a pitch behind Sano's back, and Sano pointed and yelled at Boyd. McCann stepped in to keep Sano from approaching Boyd and his glove hit Sano in the face, leading to Sano's response.

Boyd's behind-the-back toss came after teammate JaCoby Jones was hit in the mouth by an errant Justin Haley pitch earlier in the game.

Molitor expects a quick decision, perhaps before Friday's game against Boston.

"Friday will probably be the day we know if he needs to sit one or not," Molitor said.

Tepesch to start

Righthander Nick Tepesch has been named the starter for Saturday's game against the Red Sox.

Tepesch, who will make his Twins debut, was a late cut from camp but posted a 2.00 ERA in three starts at Class AAA Rochester. The Twins called him up last week just in case a long reliever was needed, but he has yet to pitch in a game.

With the Twins going back to a five-man rotation, they needed a starter and tabbed Tepesch. Fans would like to see prospect Jose Berrios get another chance, but Molitor said Tuesday that Berrios needs more polish and will remain at Rochester for now.

Etc.

• Oakland placed lefthander Sean Doolittle on the 10-day disabled list because of a shoulder strain and designated righthander Cesar Valdez for assignment. Righthanders Bobby Wahl and Josh Smith were called up to replace them on the roster. That left the Athletics with only one lefthanded reliever on their pitching staff. The Twins had five lefthanded hitters in the lineup Wednesday.