No, if promised 10 minutes, he has to average that over 26 regular season games.
So, regular season he needs to total 260 minutes.
Also, i think it's key that he maintains 10 minutes thru the season, otherwise he'll complain... so say, thru the first 10 games, try to have him at at least 100 minutes.
By the way, if you promise a start, he just needs to start in 22 of the 26 games (85%), but it's key that he maintain 85% throughout the regular season.