Jacksonville Jaguar quarterback Byron Leftwich got the go-ahead Wednesday from Coach Jack Del Rio to start against the Minnesota Vikings on Sunday.
Earlier this week, Leftwich said he was ready to start after sitting out the last two games because of a knee injury.
"He was able to work in full pads and moved around pretty well," Del Rio said after an afternoon workout.
Twelve-year veteran Jason Garrett, 38, signed with the Miami Dolphins for the remainder of the season, one day after backup quarterback Jay Fiedler was put on injured reserve because of a herniated disk in his neck.
Garrett will be the No. 3 quarterback behind starter A.J. Feeley and backup Sage Rosenfels.
Five-time Pro Bowl linebacker Zach Thomas is doubtful for the Dolphins' game at San Francisco after sitting out practice because of a hamstring injury.