LAKELAND, Fla. -- Felipe Paulino received good news and bad news on Wednesday after he was examined by team medical director David Lintner in Houston.

The good news -- an MRI and other tests showed that the structures in his sore right arm are sound, with the official diagnosis categorized as a pinched nerve in his upper right arm.

The bad news is that the right-hander will not throw for a minimum of one month, which not only takes him out of the running for a starting job this spring but cuts into his time on the mound during the regular season for Triple-A Round Rock.

"He'll do everything else to keep his conditioning up, but Dr. Lintner was specific in saying, 'No throwing,'" general manager Ed Wade said. "Throwing is out of the question for a month."

Paulino, considered one of the organization's top pitching prospects, was experiencing arm discomfort for quite some time this spring but did not make the athletic training staff aware of it until recently. He flew to Houston to be examined by Lintner on Monday.

Paulino was one of 11 pitchers who began Spring Training with a chance to make the starting rotation. That number has decreased to nine, now that Paulino and Fernando Nieve are no longer in the mix.

"It's disappointing that we have to pull Felipe out of competition," Wade said. "He was throwing the ball well. It really was never a case of him having any sort of decrease in velocity. A non-surgical issue is a little bit easier to swallow, but we certainly would like him to stay in the mix."

All things considered, manager Cecil Cooper was relieved when he heard the diagnosis.

"When you think of everything that's happening, yes, that's not bad news," Cooper said. "We'll have to wait and see what happens. I'm a little disappointed to hear it, but at least there's no structural damage. That's a good thing. He's a young guy. He'll bounce back pretty quick."

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Further on the injury front, Cooper confirmed on Wednesday that right-hander Chris Sampson is recovering well from the stiff neck that prevented him from taking the mound against the Reds the previous day. Sampson, who suspects the discomfort stemmed from sleeping in an awkward position, could resume pitching in a few days.

"Sammy's in the picture," Cooper said. "He was never out of the picture. We'll continue to get him innings. He was one of the guys who was going to be stretched out [as a starter]. We'll reassess it in the next couple of days and we'll see where he fits."

Kazuo Matsui, who is recovering from a condition called anal fissure, is working out at the Astros' Kissimmee, Fla., complex, and Cooper hopes to insert the second baseman into the lineup this weekend.

"I saw him this morning, and he said he's better," Cooper said. "I don't know if medically they'll let me do it, but I'm shooting for the weekend, possibly as a [designated hitter]. If we can do that, I'd be real happy. We'll shoot for that and see what happens."