Jackson still is recovering from that torn anterior cruciate ligament. But he's nine months into his rehabilitation, far enough along to try a full-contact practice on Monday. The knee isn't swollen. In fact, it feels pretty good. So now the vigil is on: Can Jackson return to the lineup for the opener? Should he? How soon is too soon?
"You have to be smart about the whole thing," Jackson said after practicing again Tuesday. "It may feel good right now, but tomorrow – who knows? It is hard. I think this whole process, since training camp to right now, has been great."
There is much at stake here, beginning with Jackson's long-term welfare. The standard logic is that athletes have to listen to their bodies in a situation like this. But isn't your brain part of your body? How do you factor in what it has to say? A football player's brain is hardwired to say "Go," especially when the player's teammates need him.
"I'm a part of this team," Jackson said. "Whatever they're going through, I'm going through. If they're not playing well, I'm not feeling well. If we're playing well, I'm happy for the team. My mind-set is not, 'Rush out there and help the team.' My mind-set is, 'Be healthy enough to contribute to the team.' That's how I'm taking it."
It is a tricky equation, one that affects several other linemen. Left guard Todd Herremans, who is coming off a foot injury, played last week in his first preseason game. Guard/center Nick Cole, Jackson's top backup, has missed time because of a knee injury.
Leg injuries rob some players of their speed and limit their ability to make sharp cuts. Like everything else, it is more primal for offensive lineman. Asking a knee or ankle or foot to support more than 300 pounds already is asking a lot. Asking that after a serious injury is asking for further trouble.
So the Eagles find themselves in the precarious position of needing several of their biggest men to get healthy, stay healthy, and play effectively. There is an uncomfortable amount of finger-crossing and wishful thinking in play here.
They find themselves in this position because last year's finger-crossing and wishful thinking didn't exactly work out. The Eagles made an audacious attempt to rebuild their line on the fly without bookend tackles Tra Thomas and Jon Runyan. On paper, the plan to build around Shawn Andrews with his brother Stacy and old pal Jason Peters looked pretty good. Unfortunately, the foundation just wasn't stable.
Shawn Andrews left a hole at right tackle that Winston Justice managed to fill. Stacy Andrews created a hole at right guard. Herremans missed the beginning of the season, Jackson the end. Peters was solid at times, wobbly at others. Somehow, and the mind reels at this even now, he went to the Pro Bowl.
A year later, Peters and Justice are back at the tackle spots. Stacy Andrews continues to look out of place at right guard, although it isn't clear whether that's because he should be at tackle or on the waiver wire. Herremans and Jackson, if healthy, are the left guard and center.
There was a funny moment Tuesday when coach Andy Reid was asked whether his first-team line would play at all in Thursday's final preseason game.
"No," Reid said. "The starters won't play in this game, no."
Who does that even mean at this point? The "starters?" Mike McGlynn? Max-Jean Gilles?
Reid has his methods, and he doesn't play starters in the fourth preseason game. That's fine. It also means there's a very good chance the offensive line that takes the field against the Packers is starting together for the first time in 2010. It means there's a certainty the offense as a whole will start the season without building any continuity or positive momentum in the preseason.
In a way, Jackson and Herremans are the least of the Eagles' worries along the line. At least we know that when they're healthy, they can play. It would be comforting to know that about all of their linemates.
Contact columnist Phil Sheridan at 215-854-2844 or email@example.com. Read his recent work at http://go.philly.com/philsheridan.