Unlike in the NBA and MLB, NFL players aren’t guaranteed the entirety of their contracts. Sure, they’re guaranteed part of it, but when a player signs a five-year, $100 million deal, he might only get $60 million guaranteed. Still a substantial amount of money, obviously, but if you compare that to MLB, it’s a massive difference.

NFL players are unlikely to ever receive fully guaranteed contracts like other sports, given the frequency in which they get hurt or rapidly decline, which doesn’t benefit them at all. However, with the salary cap ballooning each year, contracts are getting richer and richer with each passing season.

When the salary cap was instituted in 1994, it was set at $34.6 million. In each of the past four years, it’s risen by at least $10 million, resulting in the cap being $167 million for 2017. That’s a massive number, which is great for players. It means larger contracts and significantly more money than they were receiving 13 years ago.

No one’s disputing that fact – just look at A.J. Bouye’s five-year, $67.5 million deal – but why are some players settling for one-year deals? It’s a trend that’s become more evident in recent years, culminating in a boatload of “prove-it” contracts so far in this year’s free agency.

It’s especially notable among young players who are just entering their prime.

In 2013 and 2014, 13 players under the age of 30 signed a one-year contract worth at least $2 million. In 2015, there were 21. Last year, 17 players signed such contracts. In 2017, after about a week and a half into free agency, a whopping 24 players under 30 have already inked one-year deals worth at least $2 million.