After a couple of tasty exchanges in the early moments, Aspinall fell to the canvas, clutching his knee.
The Brit was in agony as he appeared to land awkwardly on his right foot after producing a low kick on his opponent.
With Aspinall unable to continue, Blaydes was handed the victory by technical knockout.
Despite coming out with the win, the American was clearly frustrated by the outcome, saying: "I wish the injury hadn't happened, we didn't get a chance to showcase our skills.
"I wanted to come here and make a statement. I know a win over him would have meant a title shot and prove that I'm legit."
With five stoppage wins in his first five UFC outings, Aspinall has become one of the UK's biggest MMA stars. What's more, many in the sport have touted him as a future champion.
Victory over Blaydes would've put the Manchester fighter on the verge of a title shot, but his priority will now switch to dealing with his injury.
Looking back at the incident, former UFC champion Michael Bisping told BT Sports: "It is awful. I had a quick chat with the doctor and he thinks it's the MCL. It's an extremely agonising injury.
"Tom is a warrior, Curtis is all class and it's so sad," he added. "Injuries happen, it's a freak occurrence but it's sometimes part of the sport."