MESA, Ariz. -- The Cubs lost an infielder, named their backup catcher and may have taken another step in putting Mike Olt on the Opening Day roster.
On Wednesday, manager Rick Renteria named John Baker as the backup to Welington Castillo, with Eli Whiteside headed to Triple-A Iowa. The Rangers also claimed infielder Donnie Murphy off waivers from the Cubs, and catcher George Kottaras was placed on unconditional release waivers.
With the moves, the Cubs are down to 32 players in camp, with three pitchers -- Jake Arrieta, Kyuji Fujikawa and James McDonald -- expected to open on the disabled list. That number also includes Whiteside.
With Murphy going to the Rangers, that would appear to open a spot on the roster for Olt, who has been battling for the third-base job. It's down to Luis Valbuena and Olt, and Renteria would not commit to his Opening Day starter.
"We're going to continue to play out with what we have with the guys we have in camp now, seeing them and hopefully being able to come to a conclusion here, hopefully in the near future," Renteria said.
Olt appears to have overcome vision problems that bothered him last season, and he entered Wednesday's game batting .277 in 16 games with five home runs. Valbuena, who was the regular third baseman for the Cubs last season, was hitting .263 with six home runs. The Cubs acquired Olt from the Rangers last July in the Matt Garza deal.
Renteria has some history with Baker; they were together in the Padres' system in 2012-13, but he also knew Kottaras, who played for the Padres in 2006. Kottaras had signed a one-year, $1 million contract with the Cubs; Baker and Whiteside were non-roster invitees.
"I think Bake worked really well this spring and he kind of just earned his spot in general," Renteria said of the decision, saying they liked the "well roundedness" of his game.
Jeff Samardzija was OK with Baker, who has entertained the Cubs players this spring with his guitar and interesting taste in music. His picks have included a New Zealand band, "Fat Freddy's Drop," and also a Santa Barbara, Calif., group called "Rebelution."
"He's a vocal guy and he's a smart dude," Samardzija said of Baker. "You definitely enjoy a cerebral catcher for sure. It's nice even when he's not catching that he's paying attention to the game and is locked in. Even after the game, you can bounce ideas off him.
"He's an honest guy, too," Samardzija said. "That's the best thing you want out of a catcher is, hey, if I was garbage that day, tell me I was garbage. If I was good, tell me I was good. You want that honest feedback from a catcher."
What about Baker's musical talents?
"He's good enough," Samardzija said. "You've got to look out for the mediocre guys who think they're good. Those are the annoying ones. They only know about a minute of every song they play. He can actually play and sing a little bit. And he plays good music, too."
The Cubs were looking for someone with experience and who was willing to accept his role, and Baker fits both those categories.
"Our backup guy needs to be a veteran, mental guy who's been around and knows what he's talking about," Samardzija said. "On top of that, Bake can hit, too."
Murphy knew a decision was coming. Earlier Wednesday, he told MLB.com he was trying to stay calm.
"The last week is always stressful, no matter what your situation is, until you see the final 25 people out there, until they say, 'Hey, you're going with us,'" Murphy said. "At the same time, we're here playing baseball, and just go play. If you start thinking about that stuff, you'll start pulling your hair."
Arrieta seeing good signs in recovery
MESA, Ariz. -- Jake Arrieta, slowed this spring because of tightness in his right shoulder, threw three innings in a simulated game on Wednesday, and he was confident it won't be long before he can join the Cubs' rotation.
"I'm progressively getting stronger and more and more comfortable every time out," Arrieta said after the workout. "Today was a reminder of where I will be in the next couple weeks. Health is good, body strong.
"I was glad to get that up and down three times out of the way and go from here," he said. "We'll see how I respond tomorrow. I anticipate some soreness but to feel normal after an outing. I'm very, very pleased with it today."
With off-days in the first couple weeks of the season, the Cubs could decide to go with four pitchers -- Jeff Samardzija, Edwin Jackson, Jason Hammel and Travis Wood -- and use Carlos Villanueva as the fifth starter when needed. Villanueva is versatile enough to be a swingman and go to the bullpen between outings.
Arrieta's next step will be a side session, either this weekend when the Cubs wrap up exhibition games in Arizona, or in Pittsburgh, where the team opens the season.
"It's been a good progression," Arrieta said. "Overall, just feeling the way I do is a good sign."
Rizzo teams with Cards' Motte to fight cancer
MESA, Ariz. -- Anthony Rizzo is wearing a new T-shirt that he hopes will help cancer patients across the country.
The Cubs first baseman has joined forces with the Cardinals' Jason Motte and his "Strike Out Cancer" movement. One player from each Major League team will promote the T-shirt -- which will be in that team's colors -- and $5 will go to Motte's foundation and $5 to the other player's charity of choice. That will assuredly benefit Rizzo's foundation, which has already hosted two walk-a-thons in Florida and a celebrity "Cook-Off for Cancer" in Chicago.
"It's nice that he reached out," Rizzo said of Motte. "I saw the Cardinals wearing them last year, and I liked it because of the cancer angle."
Rizzo does have T-shirts for his foundation and has worn shirts given to him from cancer patients he has visited in hospitals. Rizzo is a cancer survivor himself, having been diagnosed with limited stage classic Hodgkin's lymphoma in 2008.
"It's really cool that [Motte] is doing this, and hopefully one day, my foundation can be as big as that," Rizzo said. "It helps mine, it just helps the cause. That's really the nicest part that you can help out -- it doesn't matter if it's my foundation or someone else's. It's just to help the cause."
The website 108stitches.com went live on March 17, with 108 Stitches showcasing the "Strike Out Cancer" tees in each team's colors. Each is promoted by a different player who agreed to join Motte in a partnership that will benefit multiple charities. Each participating player has chosen a charity that will benefit from the T-shirts sales, and for each shirt sold, $5 will go to the Jason Motte Foundation and $5 to a charity of that player's choice. A full list of recipient charities will be listed on the 108 Stitches website soon, along with a photo of each player rep in his team-colored shirt.
"At the end of the day, it's about reaching people," Motte said. "Baseball is great and everything, but there are other really important things going on out there that affect a lot of people. Wearing these T-shirts shows people that they're not alone. They're not sitting there doing chemo by themselves where no one cares. People do care, whether it's friends, family or baseball players. There are people who this has touched and this has affected. This is something we're trying to do to get the word out there and try to raise money to help."
Some Cubs fans apparently couldn't wait for the blue shirt and purchased the red one on the site.
"I have had Cubs fans tweeting me, 'Hey, man, I'm a Cubs fan, but my mother just got diagnosed with cancer and I'm showing my support for her,'" Motte told MLB.com.
• The Cubs went 25-51 against the tough National League Central last season, which figures to be just as competitive in 2014.
"Two years ago, we were talking about our NL West record -- we were 1-16 and we improved on that last year," Samardzija said Wednesday. "Then we improved on our home record last year.
"We're crossing off boxes," he said, "but we need to do all of them at once, and definitely playing well against our division, which has three top of the line teams with [the Brewers], who rake in their own stadium, we've got some pretty formidable opponents who you play a lot and you get to know them well and they get to know you.
"That's when the little things come into play, and it's just about executing and minimizing mistakes and that's what we need to do against those teams like the Cardinals and Reds. They don't make mistakes."
The Cubs will find out quickly. Twenty-one of their first 30 games are against NL Central teams.
• Olt was 1-for-4 with two RBIs in Wednesday's 14-4 loss to the D-backs, and is now batting .275.
"The way he's been hitting hasn't been like a fluke," Samardzija said of the third baseman. "You watch him hit, he looks comfortable, confident. He swings, and he swings hard. That's what we need, we need guys who come in and know what they're going to hit, not hoping they're going to hit, but know they're going to hit. He's definitely one of those guys. Any one we have here, we're expecting a lot out of."
• Outfielder Justin Ruggiano was scratched from Wednesday's lineup because of a tender left ankle that forced him out of Tuesday's game. Ruggiano said there was some soreness, but the problem would not keep him out of the lineup during the regular season.
• Renteria has a nickname for everybody, calling Chris Rusin "Russy" and Castillo "Welly." What does he call Samardzija?
"I don't speak Spanish," Samardzija said.
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.