For obvious reasons, football careers aren't as long as in other sports. The NFL's lifestyle comes with a beating not many are able to endure, and it's a ruthless business that usually drains out the players and then throws them away.

But a handful of players always manage to stand out from the rest of the pack. Their impact is so notorious and valuable that they wind up playing for many years and cashing in millions of dollars.

However, all good things eventually come to an end, and their careers aren't the exception to that rule. With that in mind, we'll talk about Aaron Donald and the stars that may not be back for this season.

NFL Rumors: 3 Superstars That Could Retire Right Now

3. Julio Jones

Not so long ago, Julio Jones was in the conversation of the best wide receiver in the league. But injuries have been ruthless over the past couple of seasons, and he's still a free agent. There are legit concerns about his durability, regardless of his physical traits.

Jones is one of the most gifted and athletic wideouts in the history of the NFL. He's piled up 13,330 yards and 61 touchdowns throughout his 11-year career. But it seems like there isn't that much interest in his services anymore, so he might as well call it a day.

2. Rob Gronkowski

Rob Gronkowski has already stated that he could only come back to play for the Tampa Bay Buccaneers. However, he has also said that he hasn't felt that urged to be back on the field and play football again.

Gronk already retired once before coming back for the past two seasons. Considered by some as the greatest tight end of all time, he's piled up 9,286 and a whopping 92 touchdowns. Also, he has 4 Super Bowl rings and at least four NFL records.

1. Aaron Donald

Aaron Donald finally got the Super Bowl ring he deserved; the only thing missing on his first-ballot Hall of Fame résumé. Ironically, that ring may have come a little too late, as he's inching closer to retirement.

The Los Angeles Rams legend gathered accolades for every single one of the seasons he played in the NFL. He's one of the greatest, most accomplished defensive players of all time, but he insists that he only wanted to play for eight years, and that's it.