No... His morale might decrease more than normal, but it is total waste to spend 59 skill points on training new positions, never do that?? They r worth 3 Q and can make the player last another season.
And ya, ucan play MCs as ML and MR. I do that as it is not easy to find good wingers on my server, and if they appear on the TM, there is a fight over them. My MCs have performed well as ML and MR so far. Have made them play out of position only once or twice otherwise I usually play Narrow diamond with everyone on position.