Right-handers Evan Scribner and Ryan Cook, two veterans who figured more prominently in this year's plans after being added over the offseason, are also shut down for an undetermined time with strained lat muscles in their backs after undergoing tests on Tuesday. Servais said Cook has the more serious strain, but "we probably won't see either one of those in game action any time soon."
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Scribner was acquired by trade from the A's, while Cook signed as a free agent.
"It does take away a little from our depth," Servais said. "We've created a lot of bullpen depth. You lose two guys with the same injury, which is kind of freak, it does affect it. It's an opportunity for other guys to step up, whether it's Justin De Fratus or Joel Peralta. Those guys have thrown the ball very well so far."
As for Hultzen, the 2011 first-round Draft pick felt stiffness in his left shoulder on Sunday and the issue hasn't cleared up, which is of large concern given his history. Hultzen has pitched only eight innings of Minor League ball since undergoing rotator cuff surgery in 2014.
"I don't see when he'll be in a game," Servais said. "I don't know. It's too bad. We thought we'd bring him in, see where he was at, using him exclusively as a reliever. It's all about how he bounces back. The day he got out there, he was moving along very good, but he had a setback."
"It's disappointing, but I'll be OK," Hultzen said. "After I threw live BP, it didn't feel very good. That was our main concern coming into Spring Training, how I'd respond to everything. When I was out there, I felt fine. It's just the recovery that's not very good right now. But if I need a couple extra days, then so be it. Or a few more or whatever it may be."
Hultzen said the plan for now is just to rest the shoulder. He believes he'll return at some point this spring.
"I don't want to look too far forward. All I can do right now is see how it responds," he said. "It's really, really frustrating. I didn't see that coming. But we'll think in the short term for now. They've just said to back off and see how it goes for a couple days without doing anything, then we'll figure it out from there."
The word is better with Furbush, who pencils in as the left-handed setup man. He posted a 2.08 ERA in 33 games last year before going on the disabled list with a slight rotator cuff tear. Furbush didn't require surgery, but he has been brought along slowly this spring. He threw his second batting practice three days ago without issue.
"Charlie is on progress, on plan," Servais said. "We'll be cautious on that, too, because we want to have him the whole season. We don't want to rush him out there for Opening Day, be able to use him and then lose him at some point in the year. So we're going to be cautious on that one."
Furbush will likely throw at least one more simulated game before he's allowed to see Cactus League action.