Florida / Texas Tech Denied Substitution

[Camron Rust]

With just under a minute to go in the game, Florida takes a shot. The shot is an airball and goes OOB on the endline. They decided to check the clock to see how much time was left when the ball went OOB.

Once they have that all figured out, they denied a player entry into the game, then they allowed him in, then they sent him back out????

The ball was dead because of an OOB violation, not because they stopped the game to check something. Why was the player not permitted to enter?