By Jason Grey, Special to SI.com

	Oliver Perez hasn't come close to matching his 2004 performances. Andy Lyons/Getty Images

The question on many owners minds is: What is wrong with Oliver Perez?

And is his latest trouble the harbinger of a major injury? The latest word is that Perez will skip a start because of shoulder stiffness suffered during his outing against the Diamondbacks this past Friday. He was pain free during a throwing session on Tuesday but will miss a start as a precautionary measure.

I recently spent a week covering the Pirates, and talked to everyone from manager Lloyd McClendon to pitching coach Spin Williams to Perez, and although every one has maintained from the beginning that physical issues were not to blame for Perez' poor start (and there indeed may be some truth to that), they are saying something different now.

Obviously, the statistics indicate something is awry, but beyond the ERA and WHIP is the fact that his K rate is down to almost seven, four less from last year. His walk rate is also very troublesome, with a close to 1:1 BB:K ratio.

Over the course of my time covering the Pirates, Perez was a frequent topic of conversation. Right before his last start, McClendon told me: "From a physical standpoint, he's ready to go; now it's just a matter of performing." Perez also said "Everything feels good, everything's OK."

Much has been made of Perez' velocity. It hasn't been as bad as people think. Perez, at this time last year, routinely hit 92-93 mph with his fastball, and he's around 91-93 this season. The difference is that last year Perez was able to reach 95 at times, particularly with two strikes. He hasn't been doing that this season. McClendon, again before his last start, told me he could throw 95 anytime he wanted to, but hadn't been doing it because he was taking a little bit off trying to throw strikes. It could be that his mechanics may need a little tweaking to get his consistency back.

The interesting thing is the Pirates reportedly wanted Perez to be a little more economical this season, and stop trying for strikeouts. Should they be doing that with one of the premier strikeout pitchers in baseball? There was a lot of speculation that Perez was just getting pulled in different directions, being told to be more aggressive, and to try to get more ground balls and fly balls.

Perez has stated he's not worried about throwing hard, just trying to get outs. He's been repeatedly told to keep the ball down in the zone and stop leaving his pitches up, and that's what he is concentrating on. We talk a lot about young pitchers needing to learn how to pitch and not just throw, but it seems that Perez needs to worry less about trying to hit a particular spot and more about  throwing the ball the way he is capable of. Perez also did not pitch in winter ball for the first time this offseason, so he may not have been as sharp as usual when Spring Training started. The shoulder stiffness he experienced this spring was considered partially a result of that, although Perez attributed it to sleeping on it the wrong way.

The Pirates, especially McClendon, who is one of the better managers in baseball in monitoring a pitcher's workload and pitch counts, were very happy when they convinced Perez to not throw this winter. As McClendon put it: "This arm was on a collision course with some serious injuries, just amassing those amounts of innings every year. You just can't do it."

However, Perez was given an offseason throwing regimen that he did not adhere to, which also may be a contributing factor to his poor start.

Both Williams and catcher Humberto Cota have stated that the biggest issue with Perez is confidence. His poor start has led to doubt, and he doesn't trust his stuff when he should.

This of course, assumes that all of these issues are somehow mechanical, or conditioning, or confidence related...and not related to his continued shoulder problems.

The easy answer is to say: "It was shoulder trouble, that's the cause," and that may be the case. There are a host of other factors involved here. The shoulder trouble might even be related to Perez' mechanics being off, and that a renewed emphasis on mechanics, which is what the Pirates say they are going to work on in Perez' downtime, will cause his throwing arm's muscles to be used in the way they are accustomed to and alleviate the shoulder trouble. Changes in mechanics, even slight ones, can make the arm susceptible to problems, because the arm is being used in a way it's not quite used to. The Pirates will get back-to-basics with Perez throwing motion in order to try and get him back on track.

The bottom line is that the issue is too complicated to boil it down to just an injury situation. If you have Perez right now, his trade value is down so low that it's worth it to you to just hang on. However, Perez' upside indicates a buying opportunity. There's never a better time to get a guy as when he is hurt. Sure, the stiffness could be a precursor to something more serious, but the potential reward makes him worth exploring. If the cost of acquisition is right, you take a risk that the injury is nothing serious, and that Perez can find some of his old swagger.