Mariano Rivera Retirement: Why We'll Never Watch Him Pitch Again in MLB

New York Yankees closer Mariano Rivera injured his right knee, according to the YES network, while shagging fly balls during pregame batting practice for Thursday night's game in Kansas City.

He was subsequently carted off the field and sent to a nearby hospital for an MRI.

Original reports suggested that it could either be an ACL injury, a sprained knee or a twisted knee.

The MRI results have since come back positive, tweets Bryan Hoch, and he's likely to be placed on the 60-day disabled list with a torn ACL.

Rivera has already hinted to ESPNNew York at a possible retirement after the season, but his plans are now up in the air because of the injury.

Unfortunately for the Yankees and their fans, this is likely the last we'll ever see of the greatest clutch performer in baseball history.

Knee injuries are tough for any player to come back from, especially for a 42-year-old closer with 18 years of major-league experience.

Typical recovery time for a torn ACL is eight to 12 months, so that would likely put Rivera on track to return sometime around next spring if he decides to keep pitching.

Rivera may be a fantastic athlete and in great shape considering his age, but it may not be worth his time to rehab and come back to pitch.

Even with a pitcher of Rivera's caliber, a season-ending injury is not conducive to maintaining a high-level of performance.

Should Rivera return after a season away form the game, there's a good chance that he won't be the same dominant closer that we're used to.

He'd probably like to retire on top with a strong season, so calling it quits because of the injury is a real possibility.

There's really not much more left for him to accomplish, as Rivera has already accomplished more than most closers could dream about.

He has been a member of 12 All-Star teams.

His 608 career saves are 279 more than the next active closer (Francisco Cordero).

His 42 postseason saves are the most all-time, 24 ahead of the next active closer (Brad Lidge).

His five World Series rings are sixth most all-time, tied with teammates Derek Jeter and Andy Pettitte and former teammate Jorge Posada, among others.

Oh yeah, and he's a sure-fire, first ballot Hall of Famer.

Need I continue?

Rivera has achieved more in this great game than nearly every other player in history.

He is a stand-up guy and one of the most legendary Yankees of all-time.

Unfortunately, we may never see him don the pinstripes in the ninth inning ever again.