Shawn Andrews is an enigma wrapped inside a right tackle wrapped around a Pro Bowl guard. Andy Reid and the Eagles have known that for years, which makes their risky off-season gambit all the more fascinating.

The Eagles went out of their way to build the foundation of their new offensive line upon the most unstable fault line on their roster. It was bound to be difficult to move on from the Tra Thomas/Jon Runyan era. By making Andrews the linchpin of their entire plan, the Eagles attempted a high-risk, possibly high-reward maneuver that could make or break the 2009 season.

Yesterday, for the second week in a row, Andrews held court at his locker in the NovaCare Complex. His main message was that his back feels better and that he believes that he will be ready for the season opener at Carolina on Sept. 13.

Somehow, though, that upbeat message got lost in a bewildering array of comments, revelations, and analogies that caused more alarm and concern than they alleviated.

A few days earlier, in his role as sole provider of information about player injuries, Reid told us that Andrews' back had no structural damage. An exam by a specialist in California revealed only some muscular discomfort.

Andrews' story was very different. He said he was under full anesthesia - Diprivan, the drug linked to Michael Jackson's death - and had two injections: an epidural and a facet blocker to numb pain in his back.

"I don't think people get epidurals for just muscle-related issues," Andrews said. "I'll just say that. I had two shots in my back, and I was put to sleep. You tell me if that's a guy who wants to not play football."

Andrews also disclosed that he has had acupuncture treatments and tried doing yoga, all in an effort to get his back right so he can play football. And all of that sounds wonderful except for the simple fact that Andrews, who missed most of last season with a back injury, still hasn't practiced and doesn't know when he will.

It's always dangerous to guess how injured a player is or whether he's trying as hard as possible to rehab and get back on the field. With Andrews, things are complicated by his self-proclaimed bout with depression-related issues last summer. It is impossible for Reid or the other coaches or the players or the fans to know what's going on in Andrews' back, head, or heart.

Andrews is aware that people are wondering about all three areas. Two years ago, Andrews missed the entire preseason with an ankle injury. He told reporters he'd gotten bad news from the doctor - a "tearjerker," he called it - but then started the season opener. Last year, he missed the preseason with his depression issues.

"I would be pretty [ticked] off if I felt a guy was cheating himself or cheating the team," Andrews said.

The Eagles were well aware of all this history, yet the revamping of their offensive line depends on Andrews' moving from right guard to right tackle. And it depends on Andrews' brother, Stacy, playing right guard. And it depends on Andrews' college teammate, Jason Peters, replacing Thomas at the vital left tackle spot.

Peters and Stacy Andrews have both been fine players, but there's no denying that the Eagles committed $100 million to help create a comfort zone for Shawn Andrews. As it turned out, none of the three has spent much time on the field during training camp. Peters injured, then reinjured his quadriceps. Stacy Andrews is rehabbing a torn knee ligament. Left guard Todd Herremans is out now, too, with a foot injury.

There is no chance the starting five will line up for even a single preseason snap. Either that is a very bad sign for the Eagles or the entire ritual of training camp and preseason games is a farce. The answer is likely somewhere in the middle: The line situation is alarming, but these are established players who should have time to get themselves up to speed once they are healthy.

No one is wondering whether Peters or Stacy Andrews or Herremans really wants to come back. It is his unique history that has people asking such questions about Shawn Andrews. It doesn't help that his answers are accompanied by cryptic asides.

"I feel like I've done everything but die," Andrews said of his battle with depression.

He said he sent Reid a text message before camp: "I'm ready to sell out like a Michael Jackson concert" - an odd choice of words given the pop star's death on June 25.

"I'm at the zenith of my happiness," Andrews said at one point, and something in the manner of the enigma wrapped inside an offensive lineman made those words sound less than reassuring.

Contact columnist Phil Sheridan at 215-854-2844 or psheridan@phillynews.com. Read his recent work at http://go.philly.com/philsheridan.