Twins center fielder Denard Span returned to the 15-day disabled list Thursday with migraine symptoms, making it uncertain when or if he'll return this season.

Span suffered a concussion June 3 and missed 48 games on his previous trip to the DL, but head trainer Rick McWane said Span's symptoms now are more similar to the vertigo and dizziness he began experiencing in 2009.

"It's not concussion symptoms," McWane said. "The concussion stirred up a previous existing condition. These are migraines that present themselves not as a headaches but as dizziness and vertigo."

Span was batting .300 when he suffered his concussion. After returning from the DL on Aug. 2, he batted .057 (2-for-35) in his next nine games.

"My first two or three games in Anaheim, I felt fine, and all of a sudden some of these symptoms started coming back a little bit," Span said. "It's not as bad as two months ago, but it's still bothering me. I don't think it's smart to be on the field. I'm not helping myself and definitely not helping my team."

Span, 27, continues to consult with a concussion specialist in Pittsburgh. He tried taking medication but stopped because it wasn't helping.

"I wouldn't say I feel foggy and dizzy 24/7; it just kind of comes and goes," he said. "Once I do get going, I feel fine, but it's just been tougher to get going."

For now, the focus is on getting Span healthy, if not for the end of this season, then for 2012.

"Right now, we're just trying to figure out how to get this under control so if it presents itself down the line, we know how to deal with it," McWane said. "We'd like to take the next month and half to try to get him feeling good, so going into next year we have a grip on it, if we have to deal with it."

Cuddyer update Michael Cuddyer's MRI exam showed a small herniation in his neck, McWane said, noting that this is similar to an injury Cuddyer experienced five years ago.

Cuddyer received an epidural injection Thursday, which should give him some relief in the next day or two, McWane said.

Cuddyer hasn't played since Aug. 10, so if he doesn't feel better soon, the Twins might place him on the DL. This could lead to Joe Benson getting promoted from Class AA New Britain.

Benson, who is on the Twins' 40-man roster, hit two home runs Wednesday. He entered Thursday batting .283 with 13 homers, 54 RBI and an .868 OPS.

"Cuddy seems to think in a day or two he'll be ready to swing," manager Ron Gardenhire said. "If that doesn't go as quick as we would like, then I'll put him on the DL."

Etc. • Jason Kubel missed Thursday's game while tending to a family matter, but he's expected to return Friday.

• On Friday night, the Twins will honor Joe Nathan for becoming the team's all-time saves leader.

• The Twins signed St. Paul Saints lefthander Caleb Thielbar to a minor league contract. Thielbar, who went to Randolph High School, is the first Saints player signed by the Twins.