CHICAGO -- Ian Stewart has been dealing with soreness in his left wrist for more than a year, and he's hoping to find answers as to why when he sees a hand specialist next week.

The third baseman, who was hitting .201 in his first season with the Cubs, was placed on the 15-day disabled list Thursday. The team purchased the contract of infielder Luis Valbuena from Triple-A Iowa.

"In a way, you hope there is something there," said Stewart, who will see a specialist at the Cleveland Clinic. "It has lingered for over a year, or about a year, and nothing has come up. Maybe he'll see something different. I should know early next week."

Stewart, 27, has tried to play despite the discomfort, and for the last month, has tried a more extensive wrap which the Cubs' athletic trainers came up with to give him some support. It wasn't working. This season, Stewart has five homers, five doubles and two triples in 179 at-bats over 55 games.

He's looked great in batting practice.

"It's a little different in the game, because in [batting practice], the guy's throwing 50 miles an hour and you have a lot more control of your swing and the way it feels," Stewart said. "In the game, you have no control over anything. You're playing hard and you don't really know where the ball is going to be, and you're changing your swing depending on breaking balls.

"I was trying to battle through that," he said. "If I wasn't going to be able to go out there and really produce and help the team, there was no sense in being out there if it was hurt."

Stewart's wrist has been examined extensively and he's had MRIs. Nothing shows up on the tests.

"It was always there in the back of my mind that something wasn't right," Stewart said.

He has experienced some tingling on the outside of his left hand, so the problem could be nerve damage. He hopes to get answers next week.

"You don't ever want to be hurt, but when something lingers like this, you almost hope they can go in and find it and fix it, and you move on from that and it's behind you," he said.

Castillo back from DL as Cubs designate Hill

CHICAGO -- The Cubs activated catcher Welington Castillo from the disabled list on Thursday, and Koyie Hill was designated for assignment.

Castillo had been sidelined with a right knee sprain since May 19. In five games with Double-A Tennessee on a rehab assignment, Castillo was 4-for-11 with two home runs.

Hill was 7-for-39 in 11 games after being acquired from the Reds for cash considerations on May 19. This was his second stint with the team after spending all or part of the last five years with the Cubs. He had been playing at Double-A Pensacola and was added when the Cubs lost three catchers in a matter of days to injuries. Geovany Soto is still rehabbing from arthroscopic knee surgery.

"[Hill] filled a spot, and we were very lucky to pick him up," Cubs manager Dale Sveum said. "He filled a big void for us with [Castillo and Soto] going down on back-to-back days. Hopefully, we keep him in the organization for depth. He's such an ultimate professional, you'd like to see him get claimed on waivers, too, and get to the big leagues."

Castillo began the year at Triple-A Iowa, where he hit .320 in 16 games. He was called up to the Cubs on April 28 after Steve Clevenger was injured. In seven games with the Cubs, Castillo was 5-for-27 (.185).

Extra bases

• The Cubs didn't waste any time putting Luis Valbuena to work. Called up from Triple-A Iowa to take Ian Stewart's spot on the roster, Valbuena started at third base on Thursday in the series finale against the Tigers.

He was batting .303 in 58 games at Iowa, and had played mostly second base.

"We got him for a reason," Cubs manager Dale Sveum said of Valbuena, who was claimed off waivers from the Blue Jays. "He plays well, hits well, and he drives the ball for a little guy."

In fact, Valbuena has a grand slam off the Tigers' Justin Verlander, who was starting Thursday.

• The Cubs play host to the Red Sox for three games, starting Friday. David Ortiz will not be able to be the designated hitter at Wrigley Field, and Sveum said the Red Sox slugger is a pretty good infielder.

"He's not going to set the world on fire with range, but he has really good hands," said Sveum, who was a coach for two seasons in Boston. "When I was there, he played first base, and I think he played first base here when we played the Cubs in Interleague Play then. He does a nice job at first. He won't get to a lot of balls. He'll catch and he picks the ball well. He does a good job, actually."

• Sveum was asked whether he followed the Red Sox after interviewing for their managerial opening this offseason. Not really, he said.

"If anything, I keep track of people I've been coaching, whether it was with the Brewers -- like with [current Tiger] Prince [Fielder] across the way," Sveum said. "I don't worry about another organization."

• Double-A Tennessee first baseman Justin Bour was named to the starting lineup of the Southern League North Division All-Star team. The game will be played June 19.