From what I can gather, Mills jammed his thumb earlier in the game. People are pointing to the fact that he is participating full in practice and that it is "not regarded as serious." However, a thumb injury in a QB can be "not serious," and allow full participation.....and yet still significantly affect grip and accuracy. This type of injury occurs when some sort of impact occurs that forces the bones of the thumb to be pushed together in a way that irritates the structures in the finger joint, resulting in pain, swelling, and stiffness. Luckily, most jams do not cause significant damage to the bone and can be treated with rest and taping. Usually the symptoms for a jammed finger will clear within 2-3 weeks if treated properly. No doubt, Mills will play through this injury, unless the joint is further injured in playing.