The 25-year-old has been ruled out for the rest of the season after suffering the injury in training in a devastating blow for a player who has battled back from three separate surgeries to repair his anterior cruciate ligaments – twice on his right knee and once on his left.
Vaughan is believed to have damaged his left knee this time around and faces going under the knife again with a recovery period of up to nine months.
The popular forward revealed he has been inundated with well wishes as he confirmed the news on Twitter.
"Gutted to be writing this is an understatement,” he posted. “I ruptured my Acl last week in training for the fourth time.
"Although it’s hard to process at the moment I will be doing everything in my power to give me the best chance to get me back on the football pitch at some point, and get that feeling back of scoring a goal.
"Thanks to everyone for the messages of support it means a lot, it’s only a matter of time until I score again!”
Rovers boss John McGlynn, who gave Vaughan his debut as a 16-year-old during his first spell in charge of the Kirkcaldy club, said he was “absolutely devastated” at this latest setback after a scan confirmed his worst fears.
"It happened in training last Thursday,” he told The Fife Free Press.
"It wasn’t in a tackle or a challenge. We were just playing a game.
“He turned very quickly to go towards the ball and went down in a heap.
“He was in agony."
He added: “It’s a massive blow for him and us. More so for Lewis who is now on his fourth cruciate injury.
"He was flying. He was scoring goals and playing great football.
"This is a massive, massive blow.”