The Wales skipper has already been ruled out of his country's Six Nations championship run-in and Wales squad physiotherapist Mark Davies says the full-back must be patient on the comeback trail.
"Alfie (Thomas) is not conventional in how he conforms to advice and treatment," claimed Davies.
"As soon as he comes out of plaster, he wants to get back playing.
"He has undergone as big an operation on your thumb as you can have. He has been saying a week out of plaster, and he is going to be back in action, but I am sure that reality will strike in the cold light of day.
"He will come out of plaster very stiff and having to restore mobility in his thumb. I am sure he will see the benefits of what he has been told."
The Wales skipper is due to have the plaster removed in mid-April, possibly the same week as Sir Clive Woodward announces his 44-man Lions squad.