ASHBURN, Va. (January 7, 2013)—Baylor Heisman Trophy winner Robert Griffin III knows he's getting criticized for playing hurt in the Washington Redskins' playoff loss and on Monday on Twitter he defended his decision to play Sunday night.

The rookie quarterback tweeted: "Many may question, criticize & think they have all the right answers. But few have been in the line of fire in battle."

The Redskins were awaiting the results of an MRI on Griffin's right knee, which he re-injured twice during Sunday's 24-14 loss to the Seattle Seahawks.

Griffin did not appear in the locker room during the two hours it was open to reporters Monday morning.

Teammates defended Griffin, saying it's in an athlete's competitive nature to keep playing as long as possible.