Injured Player/Successive Time Outs

[palmettoref]

I have a question regarding a discussion that we had last night in our meeting. It involves a coach using successive timeouts to have his injured player allowed to stay in the game.

If A1 is injured and the coach request a TO and is granted a TO, A1 is allowed to return as long as he is ready to play at the conclusion of the TO. The discussion last night centered around whether the head coach could call a second TO after the first TO if he thought that A1 needed more time to return ----- successive TO's?
Some guys believe that he is allowed ONLY one TO for A1 to be ready to return to play and if he is not ready to play, then he must be substituted for ---- thus not granting a second TO? I can't find a specific ruling on that and want appreciate your clarification.