
Tom Brady is said to have suffered some sort of cut on his throwing hand earlier in the week that required stitches, but one report claims that was not the full extent of the damage.
On Sunday, Albert Breer of The MMQB was told by sources that Brady suffered a sprained thumb in addition to the laceration.
Per sources, Patriots QB Tom Brady suffered a collateral ligament sprain in his right thumb, in addition to the cut. Threw well on Friday, expected to be good to go today. But that's where the concern over his functionality would've been.
— Albert Breer (@AlbertBreer) January 21, 2018

While previous reports indicated Brady needed about four stitches, ESPN’s Mike Reiss said Sunday that it was actually more than 10.
Some additional context/information: On Tom Brady, he required more than 10 stitches after sustaining a cut on the inside part of his right throwing hand near the thumb Wednesday, per source. Those at practice described a bloody scene.
— Mike Reiss (@MikeReiss) January 21, 2018
Brady supposedly hit his hand on a teammate’s helmet during Wednesday’s practice, and he needed several stitches to close a wound that was bleeding heavily. He has gone out of his way to cover up the hand throughout the week and not give the media any type of glimpse at it.
Obviously, a thumb sprain is not ideal for a quarterback. That could, in theory, affect Brady’s grip strength. Some comments that Patriots owner Robert Kraft made hours before kickoff of the AFC Championship Game made it seem like Brady will be fine, but we won’t have a real answer until New England’s game against the Jacksonville Jaguars has concluded.