SCOTTSDALE, Ariz. -- The D-backs scratched left-hander Wade Miley from his scheduled start Tuesday with some discomfort in his left biceps muscle.

"We're just going to strengthen it back up and go from there," Miley said. "It's nothing serious, just a little tight and the ball isn't coming out the way I want it to, like a little dead arm a little bit, a little tired, I guess."

Josh Collmenter will start in Miley's place against the Rockies at Salt River Fields, while Patrick Corbin will start the other half of the split-squad game against the Mariners in Peoria.

The D-backs are confident that it is nothing serious and that Miley will need to miss just one start.

"He just kind of had a tired arm," Arizona manager Kirk Gibson said. "Do you keep going and pushing through it? Or do you do what we're doing and try and stay on target for Opening Day? Right now is a good time, we've still got time to do that."

Gibson referred to it as a "dead arm" situation that most pitchers experience at one time or another during Spring Training.

Miley said that when he's had the issue before, it's been during the regular season and he has just pitched through it. However, with there being plenty of time before Opening Day, he agreed with the decision to take a short break.

"I just want to get it out of the way so it doesn't bother me in April," he said.

Miley is slated to start the third game of the regular season on April 3 against the Cardinals.

Snake bites

• Left-hander David Holmberg allowed five runs in 1 1/3 innings Monday against the Cubs.

"Everything was up," D-backs manager Kirk Gibson said. "Fastball up and out of the zone, the strikes were at the top of the zone or belt high. He tried to throw his offspeed pitches to get him down and those were up, too."

• Trevor Cahill had his best outing of the spring, allowing just one run on three hits while striking out five. He did not issue a walk.

"I thought he was better," Gibson said. "Threw more strikes."

• Shortstop Didi Gregorius pinch-hit and homered Monday.

"He's been swinging the bat good," Gibson said. "He's been getting a lot of work on a back field. Very coachable."

Gregorius has not played the field this spring as the club continues to be cautious with his elbow soreness.

• Second baseman Aaron Hill left Monday's game for a pinch-runner after doubling in the third inning. Hill has been battling a stomach virus.