It did not look good Monday night when Patriots safety Rodney Harrison dropped to the ground, and it is not.

Harrison suffered a season-ending, and potentially career-ending, torn quad muscle.

Harrison, who turns 36 in December and whose contract with the Patriots is up after this season, could well have played his last down Monday night. When he was carted off the field, Harrison waved to the fans at Gillette Stadium as if he knew he was saying goodbye.

Many will root for Harrison to return, and it’s always possible he could. But if he decides he wants to play, he will be attempting an improbable comeback. This is a tough injury to overcome for an aging safety.

If he never plays again, Harrison will garner Hall of Fame consideration. A former fifth-round pick out of Western Illinois in 1994, Harrison went to two Pro Bowls, won two Super Bowls and is the only player in NFL history with at least 30 interceptions and 30 sacks.