Duane Burleson, AP
Oakland Raiders tackle Donald Penn (72) goes up against Detroit Lions defensive end Jason Jones (91) during the first half of an NFL football game, Sunday, Nov. 22, 2015, in Detroit. (AP Photo/Duane Burleson)

ALAMEDA, Calif. — The Oakland Raiders have agreed to a contract to re-sign free agent left tackle Donald Penn.

Penn announced on his Instagram account Wednesday that he has decided to stay in Oakland after testing the free-agent market. Penn had been expected to visit the New York Giants this week before reaching the deal with the Raiders.

The move to keep Penn fortifies an offensive line that is expected to be Oakland's strength this season. With newly signed free agent Kelechi Osemele stepping in at guard and Penn staying, the Raiders should have one of the best lines in the league. Center Rodney Hudson, guard Gabe Jackson and right tackle Austin Howard all played well last year and will return.