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3/20/2014 2:02 A.M. ET

Olt slated to test shoulder at third base in game

MESA, Ariz. -- Mike Olt, limited to first base and designated-hitter duties because of a tender right shoulder, is expected to make his first start at third base Thursday. Whether he has enough time to convince the Cubs he should be on the Opening Day roster is still to be determined.

The Cubs have Luis Valbuena and Donnie Murphy to platoon at third. Olt has hit four home runs this spring and was batting .258 entering Wednesday night's game.

"He's got to be healthy," Cubs manager Rick Renteria said Wednesday about whether Olt can make the team. "We can't make a determination on anything as far as where he's going to be until we know he's capable of being able to go out there.

"We've got to take it one day at a time. I can't project because I don't have that luxury. He hasn't played third base all spring. He's been working over there; he's been working at first. I need to see him out there [at third]; we all need to see him out there. He needs to feel comfortable."

Olt did some early work at third base Wednesday and got the go-ahead to play there in a Cactus League game. Acquired last July in the Matt Garza trade with the Rangers, he could provide the Cubs with some much-needed power.

"We'll take it one step at a time," Renteria said. "He's obviously swinging the bat real well this spring and I know he's played third base well in the past. I need to see him healthy. We've got [less than] two weeks left."

Villanueva ready to fill whatever role Cubs need

SCOTTSDALE, Ariz. -- Carlos Villanueva has been in the big leagues for nine seasons, and he's had to answer the same question in six of those. Where does he fit?

"I'm used to it by now," said Villanueva, a valuable swingman, who made his first Cactus League start Wednesday for the Cubs. "For me, instead of getting frustrated with any questions, it's a competition, it's fun and exciting for us and the people who are picking the guy. That's what I do."

Against the Rockies, Villanueva struck out eight over four innings and said the outing went "better than expected," even though he did serve up a three-run homer to Carlos Gonzalez. The Cubs need a fifth starter and had projected Jake Arrieta for the spot, but he won't be ready by the start of the season. Villanueva could sub until Arrieta is ready, then return to the bullpen, or the Cubs could go with lefty Chris Rusin, who has had a good spring and will start Friday against the White Sox.

"I've said it before, whatever they need me to do, I'll do," Villanueva said. "Hopefully, I'm showing again that I can do anything they ask me to do. I've talked to Rusin about it, too."

Rusin has talked to Villanueva about pretty much everything.

"Pitching, anything, tips, how things work," Rusin told MLB.com last week. "He's pretty good with that stuff. And he's funny, so he keeps it interesting."

Villanueva is all about the team.

"Maybe in the old-school way, guys were a little more upset about a guy trying to take their job," Villanueva said. "That's how it was when I came up. It seemed like the older guys were meaner back then because we were coming in to take their job and they didn't appreciate that. I can appreciate that.

"I love Rusin," Villanueva said. "He's a great kid, he's quiet, he does his work. It's not his fault, it's not my fault. We're here to compete and we're here to help this team. If it's him in the bullpen and me starting, or vice versa, it doesn't matter. He doesn't have that type of personality where he'll be selfish about it. Obviously, he wants to start. In the end, it's out of our hands. I'll talk to him and try to keep him calm and not dwell too much about it."

Villanueva may be the most interesting pitcher on the Cubs. He can make a spot start, pitch in relief, face one batter, go long, whatever is needed. Last season, he was 1-7 with a 4.50 ERA in 15 starts and 6-1 with a 3.03 ERA in 32 relief appearances.

He's also very popular in the clubhouse. His teammates made up a T-shirt last year with some of his favorite sayings. Maybe this year, they'll do one in Cubbie blue.

Will it say he's the fifth starter?

"If it's me going there, I have no problem," Villanueva said. "I can shuttle back and forth. You never know what can happen."

Castro hoping to see action in Minors games soon

MESA, Ariz. -- Cubs shortstop Starlin Castro, sidelined since March 2 with a strained right hamstring, said he can make up for missed time by getting at-bats in Minor League games. But Castro has yet to be given the go-ahead to play.

On Wednesday, Castro did not run but did take ground balls and batting practice as he continues to heal from the injury, incurred when he stole second in a game.

"I'm still working in the cage and everything," he said.

On Wednesday, catcher Welington Castillo and outfielder Junior Lake got extra at-bats in the Cubs' Minor League games. Castro said he hopes to join them soon.

The Cubs sent their strength coach, Tim Buss, to the Dominican Republic for three weeks to help the shortstop get in shape, and Castro also spent another four weeks training in Florida. He reported in good shape and at the start of camp predicted he would regain his All-Star form.

"That's still in my mind -- a big year, that's still in my mind," Castro said. "It doesn't go away. It's frustrating because I came here 100 percent and get hurt and that's why I'm frustrated. The good year that I want to have this year, it's not going away, it stays in my mind and I think it'll be a good year."

The Cubs have had Darwin Barney playing shortstop this spring, and he could start there if Castro isn't ready for the season opener March 31. Emilio Bonifacio, a non-roster invitee expected to make the team, could start at second.

Cubs launch website for Wrigley milestone

MESA, Ariz. -- The Cubs have created WrigleyField100.com to honor 100 years of history at the ballpark and share the team's season-long plans to celebrate the milestone.

WrigleyField100.com includes the unique, historic moments that have taken place at the ballpark over the last 100 years, including Cubs baseball, Chicago Bears and collegiate football games, and summer concerts. Visitors to the website can browse through Wrigley Field history from each decade, infographics about baseball and life in 1914, and "100 Great Times" that have taken place over the last century.

Fans visiting the website are invited to participate in polls to determine their "All-Wrigley Team," as well as other topics like their favorite broadcasters, concession items, traditions and Wrigley Field icons.

Some of these "All-Wrigley" candidates have already shared their favorite Wrigley Field memories on the website. More than two dozen current and former players, executives and celebrities revealed their favorite ballpark stories in videos.

WrigleyField100.com also showcases the team's plans to commemorate "The Party of the Century" during 10 decade-themed homestands complete with historic player uniforms, gameday entertainment, specialty food offerings, one-of-a-kind bobbleheads, retro toy giveaways, commemorative memorabilia, Cubs Charities' 100 Gifts of Service and more.

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