PEORIA, Ariz. -- Right-handed pitcher Brandon Maurer was held out of Friday's workout after his back locked up on him in the morning, causing him to miss his first live batting practice.
Maurer, 23, said he didn't think the issue was serious and he hasn't had any prior problems, though it came at a bad time with pitchers just taking the mound to face hitters for the first time.
"I think I just must have slept on it wrong," Maurer said. "It's just a little stiff back, that's all. We'll see how it feels tomorrow and go from there."
Maurer is one of about 10 pitchers competing for starting rotation berths this spring in a wide-open camp. After Felix Hernandez and Hisashi Iwakuma, there are no locks for roster spots among the contenders.
Top rookie prospects Taijuan Walker and James Paxton both have a chance to win starting jobs, as do veteran non-roster invitees Scott Baker and Randy Wolf as they come back from Tommy John surgeries. Returners Erasmo Ramirez and Blake Beavan are also in the mix, along with Maurer and newcomers Matt Palmer and Mark Rogers.
Maurer was the surprise of last year's spring when he earned a rotation berth with a strong camp despite never having pitched above Double-A ball. He wound up going 5-8 with a 6.30 ERA in 22 games, including 14 starts.
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. This story was not subject to the approval of Major League Baseball or its clubs.