Bale has been restricted to three appearances for Madrid since completing a summer switch to the Spanish capital, after largely missing pre-season through injury.
A thigh tear prevented Bale joining Wales for this week's World Cup qualifiers against Macedonia and Belgium, with Coleman warning Madrid that the winger needs patience after being thrown in below full fitness.
He told The Guardian: "Anyone who plays top-level professional football and you don't have a pre-season, if you expect to start any game, you are bonkers, crackers. It doesn't happen.
"If you think you can just pick up where you left off the season before, that doesn't happen either. It takes time. It doesn't matter how good you are. You can't just switch it on or off if you've missed all that pre-season.
"You are always playing catch-up so I wouldn't be surprised if it's after Christmas before we see Gareth getting into it again. I hope it's not serious but it may be some time before we see Gareth doing what he is capable of."
Madrid denied reports in the Spanish press last weekend that Bale had suffered a slipped disc in his back, as he bids to be fit for next weekend's El Clasico clash with Barcelona.