CINCINNATI -- Cubs right-hander Andrew Cashner will undergo an MRI on his throwing shoulder after feeling tightness while warming up on Monday, which prompted the team to scratch a scheduled start in extended spring camp.

Cashner, on the disabled list since April 6 with a strained right rotator cuff, was scheduled to have thrown two innings in Mesa, Ariz.

When Cashner returns, he will be inserted back into the rotation.

"Cashner's a starter, and that's what we're committed to," Cubs manager Mike Quade said.

Randy Wells, who has been on the disabled list since April 6 with a strained right forearm, will make a Minor League rehab start on Tuesday with Class A Peoria, and if all goes well, his next start would be on Sunday for Triple-A Iowa. If he passes all the tests, Wells could be back with the big league team next week.

Meanwhile, Doug Davis, who made his first start for the Cubs on Saturday, was not with the team in Cincinnati so he could be with his wife, Chantelle, who gave birth on Sunday. Davis' next scheduled start will be Friday against the Red Sox.

"He gave us five pretty good innings -- go have your baby and we'll see you in Boston," Quade said.

Cubs option slumping Colvin to Triple-A

CINCINNATI -- The Cubs sent Tyler Colvin to Triple-A Iowa late Monday to try and get the outfielder back to where he was in 2010.

"It's something that he definitely needs to go play," Cubs general manager Jim Hendry said. "He had a really good year for us, and since the first days of Spring Training, he never played up to that level.

"We're in the production business. It wasn't that he wasn't given enough at-bats. He didn't earn enough at-bats. The other guys here outplayed him, too."

No corresponding move was made.

Colvin was batting .113 and hitless in his past eight games. Last year, he made it difficult on the Cubs to try to get him playing time. This season, the struggles have been all his own.

"He needs to go down and play for a few weeks and once he does, we can go back to the plan we had for him," Hendry said. "He completely understood and was looking forward to getting some at-bats."

Before Monday's game against the Reds, a 7-4 loss, Cubs manager Mike Quade said he wanted to resolve the matter regarding Colvin.

"It's been a tough stretch for him, and growing pains can be tough sometimes," Quade said.

One option in the Minor Leagues could be Lou Montanez, who was the Cubs' No. 1 pick in the 2000 First-Year Player Draft (third overall) and is back with the team at Triple-A Iowa after four seasons in the Orioles' system. Following a 3-for-5 game on Sunday, in which he walked, doubled and had six RBIs, Montanez was batting .378 with 39 RBIs with Reno.

Extra bases

• Interleague play begins on Friday when the Cubs go to Boston to face the Red Sox, playing at Fenway Park for the first time since the 1918 World Series. The Cubs will be wearing throwback uniforms on Saturday that are modeled after the 1918 models.

Being in an American League ballpark will give Cubs manager Mike Quade a chance to relax a little.

"From a lineup standpoint, the weekend in Boston will be more fun than I've had for a while because I'll be able to give some people some opportunities," said Quade, who's had a tough time getting Reed Johnson, Jeff Baker and Blake DeWitt at-bats.

• Congrats to hitting coach Rudy Jaramillo's son, Justin, who received his doctorate in clinical psychology on Sunday from Rutgers University.

"I'm so proud of him," Rudy Jaramillo said.

• Larry Alexander, a Cubs fan who went into cardiac arrest during a game at Great American Ball Park last season, was one of the ceremonial first pitch participants. Alexander was saved by a doctor and two nurses on the TriHealth event medicine team working the game.