How can this ref sleep at night after calling off this Allonzo Trier dunk?

Arizona freshman guard Allonzo Trier was playing good help-side defense, came up with a steal, went coast to coast, split a pair of Colorado defenders and threw down a massive slam in the second half against Colorado on Wednesday night.

All that effort and Trier got nothing out of it. The referee waived the dunk, calling a foul on the floor.

Not only did the official take away one of the better dunks of the season, it was the wrong call. All a player needs to do to draw a shooting is foul is to make a motion toward the hoop. It can be a simple as a slight movement of the arm, as long as the official can recognize that the player is making an attempt at a shot.

Trier, who going full speed and in the process of going up toward the hoop was clearly making a motion for a shot. 

But the dunk being waived off was secondary to Trier and the Wildcats. Colorado knocked off No. 9 Arizona 75-72, snapping the Wildcats' six-game win streak.

Trier scored 19 points in the loss. Ryan Anderson led the Wildcats with 19 points and 10 rebounds. Colorado big man Josh Scott was a force down low, scoring a game-high 26 points, grabbing nine boards and blocking three shots.