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04/14/2013 8:37 PM ET

Oblique strain to shelve Clevenger at least six weeks

CHICAGO -- Given his history with such injuries and the alarming pain he suffered, Steve Clevenger knew what he was in for as soon as he followed through on his last swing Saturday.

Clevenger, pinch-hitting in the ninth against Giants reliever Santiago Casilla, got twisted up when he foul tipped an 80-mph curveball to end the game for a 3-2 loss. He fell to the ground in pain, with what was confirmed Sunday to be a strain of his left oblique. He's expected to miss at least six weeks, and was placed on the 60-day disabled list on Sunday.

"As soon as I swung, I just felt like somebody stuck a knife in my side," Clevenger said. "The reason I wasn't moving was I couldn't really breathe too good, so I was just staying down trying to catch my breath as quick as possible. It took a while to catch my breath."

The backup catcher, who is 1-for-8 with a run, a walk and three strikeouts in eight games this season, suffered a similar injury to his right side last April. He missed about a month.

"It was a lot worse than last year, pain-wise," Clevenger said. "They told me about six weeks right now, at the earliest. But last year they told me the same thing and I think I came back in about 4 1/2-5 weeks. It just takes time to heal."

The Cubs had been carrying three catchers, which gave manager Dale Sveum a right-handed option (Welington Castillo), a switch-hitter (Dioner Navarro) and a lefty (Clevenger) behind the plate.

"You could see how that bench was able to work correctly with having three catchers, and two of them being left-handed -- obviously Navarro's a switch-hitter -- but it kind of makes it a little bit easier on a manager to mix and match at the end of games and things like that," Sveum said. "So it's very unfortunate. [Clevenger] came into camp in great shape and worked his butt off in camp to make the team."

Clevenger played in a career-high 69 games last season, and had an excellent Cactus League season, batting .370 in 29 games. All 79 of his career regular-season games have been with the Cubs, in which he's batted .199 with a homer and 16 RBIs.

Now, his next course of action will simply be rest and treatment. Because the oblique muscle is so thin, Clevenger says, there's not much else he can do in terms of rehabilitation.

"I don't think I've ever seen one that's been less than three weeks, and those kind could be a couple months," Sveum said.

Sappelt looking forward to honoring Jackie

CHICAGO -- On Tuesday, the Cubs will celebrate Jackie Robinson Day, and all uniformed personnel will wear No. 42 to commemorate the 66th anniversary of Robinson breaking baseball's color barrier. Dave Sappelt is looking forward to that.

"It's a day that everybody should respect and at least put some kind of thought to. Even if you don't agree with it, change is what America is about," Sappelt said. "I think it's an important day. It's in the back of my mind and I'm grateful."

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As part of the pregame ceremony, Cubs Hall of Famers Ernie Banks and Billy Williams will be recognized. Williams broke into the Majors not long after Robinson and Banks, and he credits Robinson with being the pioneer who opened the door for all baseball players of color.

In 1997, under the direction of Commissioner Bud Selig, Robinson's No. 42 was retired across all of Major League Baseball in an unprecedented tribute.

Rev. Jesse L. Jackson Jr., founder and president of Rainbow Push Coalition, will throw one of the ceremonial first pitches. Jackson gave the eulogy at Robinson's funeral in Brooklyn, N.Y.

John C. McGinley will join Jackson for a first-pitch assignment. McGinley portrays Brooklyn play-by-play announcer Red Barber in the movie, "42: The True Story of An American Legend." Barber was affectionately known as the voice of the Dodgers from 1939-53. McGinley will also serve as the guest conductor for the seventh-inning stretch.

Sappelt planned on seeing "42," which tells the struggles Robinson had to deal with.

"In school, they try to teach you about everything," Sappelt said. "This is something important in history that everybody needs to know. It's something I think everybody should know -- how the world once was, and the steps we took forward together. It wasn't just black or Latin, Chinese, Japanese, it was everybody who took that step of acceptance. I think it's definitely good."

Cubs claim Loe off waivers, ink Gregg to Minors deal

CHICAGO -- The Cubs signed relievers Kevin Gregg and Kameron Loe on Sunday -- Gregg was inked to a Minor League deal and Loe claimed off waivers from Seattle -- though there are no indications at this point that either right-hander was brought on to close games any time soon.

Gregg made 40 appearances with the Orioles last season, the first year since 2006 that he did not record a save. He notched at least 22 in each of the previous five years, with four different teams.

One of those teams was the Cubs, for whom he pitched in 2009, when he went 5-6 with a 4.72 ERA and 23 saves. Gregg will report to the team's Spring Training facility in Mesa, Ariz., after spending the spring with the Dodgers. He posted a 0.82 ERA in 11 Cactus League innings, while striking out five.

Loe has spent all or part of nine Major League seasons with the Rangers, Brewers and Mariners. The 31-year-old is 33-41 with four saves and a 4.44 ERA in 306 career big league appearances, all but 47 in relief. In corresponding moves -- and with second baseman Darwin Barney set to return from the disabled list on Tuesday -- the Cubs placed catcher Steve Clevenger on the 60-day disabled list with a strained left oblique and optioned right-hander Rafael Dolis to Triple-A Iowa.

"They're gonna be be in the mix with some of the decisions we make in the next couple days," manager Dale Sveum said of the additions. "Veteran guys, obviously. Guys that have thrown strikes in the past. I know Kameron Loe from Milwaukee -- great guy. Can get ground ball sinkers. If he gets enough rest, his sinker's always really playable in the big leagues. They'll be in the mix."

The Cubs' closer situation has been in flux all season, with Carlos Marmol being relieved of the duties last week. Kyuji Fujikawa, who closed games in Japan for 12 seasons before signing a two-year contract with the Cubs this winter, took over that role before he was placed on the 15-day disabled list with a muscle sprain in his right forearm this weekend.

Sveum has since said he won't automatically go back to Marmol to finish games now. Shawn Camp and James Russell will likely be given the duties, with matchups dictating who pitches.

"Anything could change according to the score of the game and what happens after that fifth inning," Sveum said. "There's a lot of things that can happen, especially when you have two left-handers in the bullpen. We could do this to get out of a jam, we might do [something else] earlier than normal. ... There are just so many things that go into it when you don't have a bona fide closer."

Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. ‪Joey Nowak is a reporter for MLB.com. Follow him on Twitter at @joeynowak.‬ This story was not subject to the approval of Major League Baseball or its clubs.