James Holt, who was an undrafted rookie free agent in 2009 that helped the Chargers special teams immensely when he was signed from the practice squad, has been placed on Injured Reserve and will not be seen against until the Chargers 2010 mini camp. He injured his shoulder in the game against the Redskins and will be undergoing shoulder surgery to repair the shoulder.
He is being replaced by Dontarrious Thomas, who played well in limited time with the Minnesota Vikings from 2004-2006. Since then, Thomas has been mainly a backup. In 2008 he was cut by the 49ers in the preseason, and was cut during the 2008 season by the Vikings (who had brought him back). He spent 2009 with the California Redwoods of the UFL and finished the year as one of the league's leading tacklers.
Dontarrious is not a 3-4 OLB. If anything, he's an ILB in this system. The reason he was signed was because he's a big, strong guy who is a sure tackler and can help to fill the void on special teams left by Holt.