Well, if you have a better explanation, I'd like to hear it :)
Yeah, but this is a very rare set of circumstances: this team has been a bot for a long time (most teams in that league carry over 40 players on their rosters, which indicates a lot of drafts), and after becoming a bot, an 18 (or 19yo, I don't know when exactly this team turned bot) 6'2" HoF somehow filled up the sPG rosterslot, the team dropped to bottom division and it looks like he used his training time well!
Anything could have happened: training could have been set at team training FT, a starter potential player, or an overaged player could have been auto assigned to the trained roster spot, the team could have been replaced by a new 1, the trainer could have been replaced.. And still this guy somehow managed to become a $ 320 000 salary/week PG. I am not sure it is, but I can't find another explanation than bot training. And who knows, maybe there are dozens of players like that..