Ty is trying to be diplomatic in telling Taysom to make a decision one way or the other. And to do so before spring ball. Because the position needs to move forward. And the ideal situation is for that forward motion to begin in Spring Ball. If he decides later, he's set the team and position group's progress back, because then at that later time they have to almost discount everything that had been done in spring ball and go back to square one and recalculate the formula - this time with Taysom involved in the calculus.
Detmer has enough on his plate. He's trying to make his job easier and limit distractions and complications.
It's a smart move by a position coach to ask a player to decide if they want to be involved or not.