With injuries piling up from a long WWE career, Rey Mysterio may be close to retirement.

The former world champ is recovering from knee issues, a body part that has proved to be Mysterio's Achilles’ heel.

Wrestling Observer Newsletter reports (via WrestlingInc.com) that "Rey Mysterio's future is in question. When he mentioned to one company official that he tore his good knee up about a week ago, it was brought up that he should consider retiring."

After stopping and starting his latest WWE runs, news continues to worsen about Mysterio's health. He tweeted on Monday that he may have an ACL tear.

F4WOnline (subscribers only) reported that it wasn't in fact an ACL tear, but Mysterio would "need to wear a special boot and probably won't be wrestling for a while."

Could "a while" end up being forever?

This certainly isn't the first time that Mysterio has had trouble with his knees. He had knee surgery back in 2006 and again in 2011.  In addition, Mysterio suffered a concussion in August last year.

Injured-rey-mysterio_original Rey Mysterio wincing in pain, a far too common sight. (Photo from WWE.com)

At age 38, he's not ancient by WWE standards, but his high-flying style has clearly taken its toll over the years.

Mysterio began wrestling at only 14, performing in Tijuana, Mexico in 1989. It now seems that his iconic career is coming to a close.

Should Mysterio decide to pack it in, to admit that his body is just not up the grind that is WWE anymore, he should have no shame in retiring.

He has accomplished more than most and made a permanent mark on WWE. Mysterio is considered by many to be WWE's greatest high-flyer. He's won the cruiserweight title, the Intercontinental Championship, the WWE title, the World Heavyweight belt and in 2006, outlasted 29 other men to win the Royal Rumble.

Rey Mysterio video tribute

He's been one of the company's most beloved stars and helped infused the Lucha Libre style into WWE.

Fans don't need to see a Mysterio with a bum knee, to see The Human Highlight Reel at half strength or less. Mysterio doesn't have to give us anymore.

If his body just won't hold up, listening to those WWE personnel who suggested retirement is the best option available.

Time is the one opponent that WWE's ultimate underdog won't be able to defeat in the end.