However, Bale came off the bench to play the final third of Wales' 3-0 loss to Serbia on Tuesday night, and Coleman was pleased to see him back in the fold.
"He played 30 minutes but after 15 minutes he looked tired - but he has only had four training sessions, so you will not get what you normally get," Coleman said in a press conference.
"But he gave us a lift, the fans were excited and it gave us a spur, although the game was done and dusted. We needed to be in the game, it was lost by then, but it was nice for the Welsh supporters to see him.
"If he starts Saturday he will not finish the game, I would be amazed if he does. He is nowhere near ready for 90 minutes even if Spanish football is slower. He may get 45 minutes, I don't know, but he will feel better in himself after 30 minutes."
Bale has 42 caps for Wales.