I've had a few ejections. Three I think. I don't think it is a certainty that your player is foul prone, but its not a good sign. I've trained foul prone players in the past, and its difficult. In the end I had to go with just training two players, as three is just impossible if one if foul prone.
I just bought three trainees. Because they hadn't played before I had no way to check their past, but so far, out of six attempts, only one has made it through 48 minutes. He also managed over 47 minutes in one game so he seems almost sane compared to the other two. I'm in for a frustrating time I'm sure.