Rule on pitcher to pitch again??

[tfunky14]

Let me clarify, I'm involved in a adult league and had a situation that two teams disagreeded on. We go by American League rules but can't find the answer in MLB. Player A started game in outfield and came in relief for the starter in the sixth inning. Player A pitched one inning then went back into the outfield in the bottom half of the inning. Player A came back to pitch in the 11th inning. (this is where the disagreement is) Other team thinks we can't do this, but I'm 85% sure this is allowed because player A never left the field. I need to know if I'm right and can you find some facts I can see.
Thanks for your help...

[tfunky14]

This might not belong under this topic but I thought someone might be able to help me.

[raiders_umpire]

Already in General Talk.