Is he a trainee?
If not a trainee the best solution is to get a player who can compliment his abilities for difficult games. Not being sure of his stats, I can only make a suggestion, but say he can score & rebound, get a player from the TM who can rebound & defend. Or if he can do all equally, get a player who has 2 standout abilities to take advantage of opponent weaknesses.
This will allow you to pick Grijalba as backup during some league matches reducing his minutes.
I had the same problem with Holmes (SF) in my team.