GSP said that he's felt better than ever since vacating his belt and stepping out of the spotlight, and many fans and critics suspected that if he decided to make a return to the cage, he'd look fresher and more motivated.
While GSP seemed on course for a potential return to the UFC, any plans for the 170-pound legend to showcase his talents under the UFC banner once again are now on hold.
"Rush" took to Twitter, saying that he tore his ACL in training and will require surgery to repair the damaged ligament.
For GSP and his fans, this is certainly not good news.
While modern surgeries allow athletes to return from knee injuries at or around 100 percent, one has to factor in GSP's recent struggles inside the cage.
While he was not losing fights at the end of his UFC career, his dominance waned little by little, and his most recent performance against Johny Hendricks at UFC 167 was undoubtedly his least convincing victory to date.
It was clear that the stress that comes with being the champion was beginning to affect his performance inside the cage, and GSP decided to step away for the time being because of it.
Now, the Canadian superstar finds himself fighting another uphill battle, as he will need to rest, rehab and recover from this untimely injury.
It appears as if it might be best for GSP to say his goodbyes, make peace with what he's already accomplished and call it a career.
Fans or critics could question that decision, but it's difficult to see what GSP has to gain by putting his body through more torment to make a return.
For now, stay tuned to Bleacher Report as updates on GSP's injury situation emerge.