With a 12-2 record, Shane Carwin has had a pretty decent MMA career.
Carwin dominated Lesnar in the first round of their fight before gassing out and being submitted.
After a string of injuries, Carwin returned to face Dos Santos. Dos Santos dominated the fight, but Carwin became just the second man to go a full three rounds with the champ.
After the dos Santos bout, Carwin faced injuries and surgeries before signing on to face Roy Nelson.
Although Carwin's rivalry with Nelson was set to end at The Ultimate Fighter 16 Finale, the injury bug has once again hit him.
While Carwin has had issues with his back and neck before, this time it was a blown knee that took him out.
Carwin was once one of the most feared fighters in the UFC.
His first 12 fights ended in the first round, with almost all of them ending in the first three minutes.
Carwin is also a former UFC interim heavyweight champion and holds wins over Frank Mir and Gabriel Gonzaga.
But while Carwin may still have the fighting spirit, his body just does not seem to be holding up.
If Carwin were a much younger fighter, it would almost be tragic how his career has been over the past couple of years.
But Carwin is 37 and will turn 38 in a little over a month's time.
Usually athletes of any sport start considering retirement when they start pushing 40.
It does not help when you put your body in so much stress like MMA fighters do just to train.
Carwin may want to prove that he still has some fight left in him. But the safer thing for his body may be just to slow down and retire.
Since 2009, Carwin has only had four fights with a 2-2 record.
Carwin once had the knockout power to take out almost anybody. But as long as his body can't hold up, having knockout power is pointless.