Jonathan Isaac minutes question

Hi,

I'm ashamed to say I haven't been keeping up with the games due to work and family but I was wondering what's the reason for Isaac's minutes. He's playing 16 minutes per game and is it because the team is still concerned about his injury and health or if he hasn't played well enough to justify more minutes?

I noticed Tristan is averaging 26 minutes as a rookie. I don't know which reason would be worse. That Isaac still has injury concerns or he signed a new contract and is being outplayed by a rookie. Hopefully it's for another reason as I'm a massive Isaac fan.

Thanks!