Salary and capping are not directly connected. He can have high sublevels since you are still training him and could cap just before popping in several skills. His virtual salary might be a bit higher because of those sublevels, but you won't see it before next season's salary update.
According to JosefKa's potential formula, he could look something like this:
JS 9, JR 9
OD 10, HD 10
DR 10, PA 10
IS 1, ID 1
RB 1, SB 1
That's ~ 13k, starter potential with low sublevels.
Actually, he looks even better than that, so I guess, it's quite possible that he did, in fact, cap then. I just wanted him to pop one more time in OD and PA is all. And I know that, with amount of training he received so far, he is well overdue for one. If it weren't for the capping, obviously.
As for the training itself, yes, he is a pet of mine :-) All my players are, really, or I would never train them this late in their careers. I know how training works - though some of the people here expressed their doubt into that :-) - and if I weren't waiting for those guys to pop "just one more time", I would switch to normal training (training 18 or 19-year-olds) many times by now.