Patriots starting center Bryan Stork's availability for opener in question

FOXBOROUGH, Mass. -- The availability of New England Patriots starting center Bryan Stork is in question for the NFL opener against the Pittsburgh Steelers on Thursday.

The Patriots and Steelers have not yet been required to submit injury reports, but Stork has been absent from the start of New England's last two practices. He had previously been cleared after passing a concussion test, according to the Boston Herald, and was present for the start of Saturday's practice.

But things have shifted the last two days, requiring some moving parts at practice with undrafted rookie David Andrews and seven-year veteran Ryan Wendell getting the early repetitions at center. Third-year player Josh Kline is also an option.

The entire interior of the offensive line is one of the Patriots' more pressing questions, as starting left guard Dan Connolly retired this offseason. Fourth-round draft choice Shaq Mason spent the most time at that position in the preseason, although he might not be ready to assume the role full time after coming from a triple-option offense at Georgia Tech.

Wendell and Kline are also options at that spot, while fourth-round pick Tre' Jackson out of Florida State has been the consistent starter at right guard since the start of training camp and it wouldn't be a surprise if he starts in the opener.

Elsewhere at practice, defensive tackle Khyri Thornton was the only other player not spotted, which could be due to a variety of factors (possibly travel, for example) after he was claimed on waivers from Green Bay on Sunday.

"I think he's a talented guy, we'll put him in the mix with what we have there and see how it goes," Patriots coach Bill Belichick said of Thornton during a Monday news conference, noting that seeing him in the preseason opener helped in the evaluation. "He has a decent body of work through preseason last year. He's a player we want to work with, and we'll see how he's able to fit in with what we ask him to do and how he performs and go from there."