"There's a long way to go. All signs are optimistic, highly optimistic, and point to what is likely to be a full neurologic recovery. Now we've got to get there but so far things have been very very positive," said Dr Mayer.
Two physicians caring for the 24-year-old said earlier he was "demonstrating signs of good neurological recovery" and was able to communicate in writing.
Hamlin collapsed on the field after making a tackle in the first quarter of the game against the Cincinnati Bengals and had to have his heartbeat restored on the field.
The game, which Cincinnati led 7-3, was later postponed.
NFLPA President JC Tretter commented that the decision to postpone the game could have been made sooner on the night.
"For most people watching at home and for the Executive Committee, our staff, the players on the field, the coaches on the field, it was a clear 'no' (to continuing the game). And everybody knew it was a clear 'no'.
A source with knowledge of the situation told Reuters on Thursday that the game would not be resumed.
