A grade two (significant, but not complete) tear to be exact. "It was severe," Gibson said. "Doctors didn't know what we could do. They put a big cast on my hand. Oh man, I don't wish that on anybody. But it's kind of almost healed up now. (Thibs) said, 'Never give a team any kind of uphill trigger point on you to try to slow your game down.' That's why I always remained quiet and whatever happens, whatever criticism I take, that's what I'm going to take." It happened January 19th against the Cavs. More in the article.
I have two reactions. First, it explains Taj's rebounding like a shooting guard. Second, it shows Thibs is willing to stick with his guys even if he could have rested Taj and played Mirotic. Sort of like how he plays Kirk way too many minutes.
I think your second point is interesting. I think you're right--Thibs views the injuries to Gibson similarly, and is/was reticent to cut back on their minutes if they were were willing to play through them. The issue is that they're not similar injuries. Gibson's injury was sustained in a game. KH's are the product of wear and tear from a career of carrying a heavy minutes load. But since Thibodeau doesn't believing in minutes limitations the situations are the same to him.
Sticking with the vets is a reasonable thing to do. It shows a measure of respect to guys who deserve it. It's good to have at least one guy in the organization who respects the players. It also explains why the players love Thibs.