DENVER -- A Rockies bullpen that has shown significant improvement from last season will be without one of its key contributors, as the club placed left-hander Mike Dunn on the 10-day disabled list Wednesday with back spasms.
Right-hander Chad Qualls, who began the year on the disabled list with forearm tightness in his pitching arm, was activated to replace Dunn on the active roster.
The move is retroactive to Sunday, a day after Dunn's last outing, when he first experienced the pain in his middle back throwing sliders while warming up in the bullpen. Dunn, who said he has never experienced back spasms, rested Sunday and Monday but still experienced tightness Tuesday when throwing a bullpen session. He then underwent an MRI, which came back clean.
"I could throw fastballs fine and the slider, you're a little more tense on your slider," Dunn said. "You activate your muscles a little bit more, so by doing that right as I come through, everything just gets tight and it doesn't ever really release. It just kind of stays tight, so we're wanting to make sure it's completely gone, and hopefully it's the last time we deal with it."
Dunn said he will take a few additional days of rest and play catch this weekend in Arizona, where the Rockies play a three-game series against the D-backs beginning on Friday. Manager Bud Black said the lefty would be available during the second leg of their road trip, in San Diego, where Colorado plays a three-game series starting Tuesday. Dunn is eligible to come off the DL next Wednesday.
"I think I might've just tweaked it somehow. Overwork? No," Dunn said. "I've had heavier workloads before in the past. Like I said, this is the first time for me [experiencing back spasms] so we're just going to take it easy and make sure it's completely gone and not try to push through anything."
Dunn signed a three-year, $19 million contract in December as a key cog in general manager Jeff Bridich's aggressive offseason, and the left-hander made an immediate impact on a bullpen that posted an MLB-worst 5.13 ERA last year.
Dunn, who sports a 1.17 ERA in 7 2/3 innings this season, didn't allow a run until his 10th appearance.
Qualls, who's embarking on his 14th MLB season, contributed 32 2/3 innings and posted a 5.23 ERA and a 1.592 WHIP last year, his first in Colorado. He signed a two-year, $6 million contract in December 2015.
Dahl progressing
Outfielder David Dahl said Wednesday he hopes to see game action in extended spring training as soon as next week.
Sidelined since early Spring Training with a stress reaction in his sixth rib, Dahl swung off a tee for the second day in a row on Wednesday. His next step would be live batting practice, but with Thursday being a getaway day, he might not get a chance to swing on the field until the team gets to Arizona.
The Rockies' Spring Training facility is up the road in Scottsdale and extended spring workouts are underway.
"Hopefully, I might go [to Salt River Fields] in the mornings and do a full day's worth of stuff to make sure it's all good and see how that feels," Dahl said, noting that no formal rehab assignment has been scheduled.
Dahl, 23, hit .315 with seven homers and 24 RBIs last year after being called up on July 25, and tied an MLB record by recording a hit in his first 17 games. He was expected to compete with Gerardo Parra for the starting left-field job during Spring Training before the rib injury, which prevented him from any rotational activity.