Namely, that he isn't a point guard. They've spent three quarters of this season trying to transform him into one and it isn't working.
Amen is the Rockets third best player after Sengun. But neither of them can shoot. So, what's the point of running a pick and roll to get one of them open?
When Steven Adams was around and sometimes now with Clint Capela, coach Udoka rolls out the double big with Amen still on the floor. That's three non shooters.
The answer is Reed Sheppard and for maybe the best of reasons - the Rockets don't have any other choice. I don't think there is a question between him and Amen, the real question is what happens next season with Fred VanVleet comes back from serious injury. He might have to come off the bench in favor and the more dynamic Sheppard.
Amen needs fewer minutes and those minutes need to be staggered with Sengun so the Rockets can keep shooters on the floor most of the game. He needs to go back to focusing on being one of the best defenders in the league and an opportunistic dunker on the offensive side.