Modern college football recruiting is a game of now you see them, now you don’t. In an increasingly common disappearing act, many who signed national letters of intent Wednesday will sign with agents as they leave early for the NFL. Some after seeing the field for only one season.

This year’s draft includes 103 players who left school with eligibility remaining. The number of early entrants was 96 in 2016 and 75 in 2015.

Given those numbers, some of the 21 players who signed with Ohio State on Wednesday will play for only a year or two before trading in their scarlet and gray for NFL green. This year, six Buckeyes — hybrid back Curtis Samuel, safety Malik Hooker, cornerbacks Marshon Lattimore and Gareon Conley, linebacker Raekwon McMillan and receiver Noah Brown — made the jump. Brown, Hooker and Lattimore all started just one season.

Such early exits lead to increased recruiting pressure on college coaches and their staffs.

“I don’t want to say it’s awful, but it’s tough … but that’s the way it is,” Ohio State coach Urban Meyer said. “I guess we are now of the mindset that it will happen, so you prepare for it to happen. You recruit guys that are ready-made as much as you can.”

Meyer compared plugging holes created by early exits to a “flywheel.”

“You’ve got to constantly keep going and fill those spots,” he said.

Mark Pantoni, Ohio State’s director of player personnel, agreed with his boss.

“There’s some pressure to make sure when you lose a Darron Lee, you better bring in someone just as good, or the team is not as good,” said Pantoni, referring to the former OSU linebacker who left in 2016 after playing just two full seasons.

The pressure to keep feeding the beast that is big-time college football has led to an inevitable dynamic and interesting contradiction.

The dynamic: Because underclassmen leave early, recruits need to be ready to play sooner, which helps explain why more of them are entering school early. Ohio State already has nine of its 21 recruits on campus. Not only do coaches encourage recruits to become college students in what normally would be their senior year of high school; players also want to get a head start on the 2017 season, knowing their eventual time as a starter will be limited.

The contradiction: Most of the nine who already are enrolled emphasized they chose Ohio State not only, or even mainly, for the football, but for the education. Yet they would consider leaving school early for the NFL.

“The main reason I’m here is to get my degree. As long as I can accomplish that, I’m happy,” said Isaiah Pryor, a 6-foot-2 safety out of Bradenton, Florida. “I’m majoring in medical laboratory science, to be a pathologist.”

Good for Pryor, who knows what he wants and how to get there — unless in three years the NFL considers him a first-round draft pick.

Pantoni knows how it works.

“We always (want) to recruit guys that are not only great kids who want to do great things after football, but who want to play in the NFL,” he said.

Shemy Schembechler spent 16 years as an NFL scout before launching a recruiting service — GES Advisory Company — that facilitates the recruiting process for players and their parents. The son of legendary Michigan coach Bo Schembechler, he stressed that leaving college early is not the best option for most players.

“Only a shade over 1 percent make it to the NFL out of college,” he said. “It’s not a long-term solution for everybody.”

But more and more it is the way at Ohio State, because the Buckeyes are not just anybody.