Lately there has been a lot of speculation as to why former Raiders center Stefen Wisniewski has gone unsigned by NFL teams this offseason. He had reported visits with the Buccaneers and Seahawks -- with interest from several other teams -- and yet has yet to sign a deal with anyone. Now we may know why.

According to Brad Biggs of the Chicago Tribune, Wisniewski suffered a torn labrum (shoulder) that required surgery so no team has stepped up to sign him yet.

The Bears were linked to center Stefen Wisniewski at the outset of free agency and he is one of the better remaining players on the market. . . Wisniewski is recovering from shoulder surgery after last season when he played with a torn labrum. The former second-round pick of the Raiders has made visits to the Seahawks and Bucs, and the Rams and Chiefs are also known to be interested. No team has been willing to meet his request of $4 million per season and it could be he winds up on a one- or two-year prove-it contract. At this point, it would be a mistake to rule out the Bears.

It is not known exactly when Wisniewski suffered the injury. He may have been dealing with it all season. The former second round pick has been the Raiders starting center the past three seasons. He had easily the worst season of his career at center giving up 12 QB hurries -- 8 of which came in the final nine games. Playing with a torn labrum would go a long way to explaining that.

The Raiders let Wiz leave in favor of signing Rodney Hudson away from the Chiefs, making him the highest paid center in the league on a 5-year, $44.5 million deal. Hudson was the one player on the market would be considered an upgrade over a healthy Wisniewski. Having a shoulder injury that required surgery may have only stood to strengthen the Raiders' resolve in replacing him with Hudson.

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