How do you ‘prepare’ for NFL draft?

I do not understand this development, so someone might have to explain it to me.

Will Grier, a top flight quarterback for West Virginia University is the latest top-tier athlete to forgo a football bowl game to “prepare for the National Football League draft.”

Let’s ponder that for a moment. The Mountaineers are going to play a game against Syracuse in the Camping World Bowl.

Grier received a scholarship to play football in Morgantown, W.Va. The school paid for his education. The school’s fans packed the stadium to watch Grier play QB. So now he wants to exhibit his loyalty to the school by skipping the team’s final game of the year?

To prepare for the NFL draft? What in the world do these guys do to prep for a draft? Spare me the excuse that they are seeking to prevent career-ending injury; that event could happen at any time of the year.

Royce Freeman, a running back at Oregon, stiffed the Ducks a year ago. So did Christian McCaffrey at Stanford a couple of years before that. These high-profile athletes occasionally bail on their schools to, um, get ready to be drafted.

I keep circling back to a series of questions: What in the world do these fellows do to prepare to have their name called as a member of an NFL franchise? Do they run wind sprints in their front yard? Do they practice blocking and tackling in the garage? Do they, um, memorize play books?

Moreover, is there no more loyalty to the schools that shell out good money to pay for their education?