According to ProFootballTalk's Rumor Mill, takle Jonas Jennings' days with the 49ers may be over.

From ProFootballTalk:
Though many league insiders and observers are skeptical about whether 49ers left tackle Jonas Jennings was placed on injured reserve because he actually has an injury that prevents him from playing or because the team decided he was a pain in the butt and didn't want to give him the freedom that he likely craves, a league source tells us that Jennings is legitimately injured -- but that Jennings' days with the team are over.

From ProFootballTalk:
Because the 2006 Collective Bargaining Agreement removed the right of NFL teams to send players home with pay, the Niners' only ability to rid themselves of Jennings for the rest of the year without cutting him was to put him on IR. Though we presume that Jennings could challenge the injured reserve designation, he likely is content to get the balance of his 2007 base salary of $3.65 million and then hit the market again in 2008.

Signed through 2011, Jennings is due to make base salaries of $3.45 million, $4.2 million, $4.3 million, and $5.15 million over the next four seasons. In theory, he could be traded. But he likely would want more money from a new team, which could prevent a deal from getting done.