MILWAUKEE -- Cubs reliever Blake Parker was placed on the 60-day disabled list with a right elbow stress reaction Wednesday, and reliever Manuel Corpas' contract was purchased from Triple-A Iowa.

A stress reaction is a contusion, and it was confirmed by an MRI, done Wednesday. Parker will require treatment as if he had a stress fracture and won't be allowed to pick up a baseball for 30 days. He last pitched Friday against the Giants, has appeared in four games, and has not given up a run over 4 1/3 innings.

"He said it had been bothering him since Houston [May 21-23], and he just kept trying to throw through it. It got a little bit worse all the time, and he finally mentioned something yesterday," Cubs manager Dale Sveum said.

Corpas made his Cubs debut in Wednesday's 8-0 loss to the Brewers, striking out two in one scoreless inning. It was his first Major League action since 2010.

Corpas appeared in 19 games at Iowa, and in May compiled a 2.33 ERA in 10 games, giving up 11 hits and walking four over 19 1/3 innings. He struck out 13 in that stretch, and opponents hit .167 against him. Right-handers batted .161 against him this season.

Sveum said Corpas will be used in matchups against hitters who struggle against pitchers who throw sinkers.

"It's another mix to the puzzle that we have who's a little bit different than who we have out there," Sveum said.

Hoyer applauds Sveum's handling of Castro

MILWAUKEE -- When Dale Sveum was interviewed for the Cubs manager's job, he was asked how he would have handled Starlin Castro after the shortstop was revealed to not be paying attention during a nationally televised game last season and criticized on air by Bobby Valentine.

Obviously, general manger Jed Hoyer liked Sveum's response, because he was hired. Hoyer said neither he nor president of baseball operations Theo Epstein influenced how Sveum handled Castro when the shortstop made a defensive gaffe in San Francisco on Monday, forgetting how many outs there were in the inning. It was all Sveum.

"That was something we talked about in the interview process," Hoyer said Wednesday. "[Castro] had already had that Bobby Valentine moment and missed that pitch. We were hoping he'd never have another incident, and he did. That's why you hire a manager -- that's the manager's job. Dale did that on his own, and I think it was a perfect tone."

Sveum told Castro that the lapses in concentration would not be tolerated, and on Tuesday the shortstop played what Hoyer thought was his best game of the season.

"As far as how he fits in our plans, he's a huge part of our plans," Hoyer said of Castro. "He's a shortstop who can hit, who can run and he's getting better defensively. Those are hard to find. You look around baseball and almost every time we play another team, we have the better shortstop on the field, and that's a great feeling to have.

"We do have to address those [lapses], and I think Dale has struck the perfect tone with Starlin -- 'Hey, I like you, I get it, but it's got to stop,'" Hoyer said. "That's a big part of why we hired Dale, he can strike that balance. I don't think Starlin resents him for it, I think Starlin understands.

"Maybe that was a good thing to happen in the long run. I'm hoping that's the case. Maybe that's the straw that broke the camel's back from Dale's perspective, maybe that ends up being a big positive."

Extra bases

• The Cubs were one of several teams to watch free agent Jorge Soler work out on Wednesday.

"We obviously scouted him extensively -- a lot of teams have -- and a lot of teams are involved," Cubs general manager Jed Hoyer said. "We had a similar situation with [Yoenis] Cespedes this winter. It will be intriguing. We've done our work on him."

Cespedes eventually signed with the Athletics. Soler's agents have set a July 2 signing deadline for teams to submit bids for the Cuban outfielder.

"It's not surprising [a lot of teams are involved] -- he's really talented, and there is that July 2 uniqueness that adds to it," Hoyer said.

• Although the Cubs front office has been busy with the First-Year Player Draft, Hoyer said he's been in touch with teams regarding possible trades. With tight races in some of the divisions, such as the American League East, it's hard to tell who's a buyer.

"It's such a jumbled race now," Hoyer said. "It's hard to talk about a Wild Card now, because in both leagues there's a mass of teams hovering. I think that will shake out a little bit over the next six to eight weeks, and as it does, teams will be more active. I think now teams are in a wait-and-see mode to see how the next month or so works out. We'll be on the phones."

Cubs pitcher Ryan Dempster is in the last year of his contract with the team and knows he could be dealt.

"I'll do what's best for the Chicago Cubs, and if that means they want to trade me to try and better the ballclub, then I have to listen to what they have to say," Dempster said. "I realize it's a possibility, but I'm really trying to be ready for Sunday. I'd be doing everybody in here and everybody who is a part of the organization a disservice if I wasn't just preparing to do my job. All the other stuff will work out how it works out."

Dempster does have a no-trade clause in his contract.