The former England striker has returned from Colorado following a second operation, performed by renowned specialist Richard Steadman, to his knee.
And he is determined to show he is still a force to be reckoned with.
"Well, they're wrong, very wrong.
"The top specialist in the world says there are no complications, and when I come back - not if - there won't be any problem.
"Anyone who says otherwise is believing neither Dr Steadman nor me."
No return date set
Shearer is currently wearing a protective brace to stop him bending his leg with his return expected shortly into the start of next season.
"It's going to be a question of letting nature take its course, and no-one is laying down a return date for me to be playing again.
"If we said so many weeks and it turned out to be longer, people would say there's a problem.
"And if we said so many weeks and it turned out to be a shorter recovery, people would say I was being rushed back.
"So all I'll say is that it will take as long as it takes."