The British fighter, who's unbeaten in his last 10 Octagon outings, pieced up Diaz, winning a lopsided, unanimous decision.
But his victory failed to impress Masvidal who pulled no punches in a scathing attack as he eyes a return to action in October or November.
On his return, he said: "Whoever's in the top five available November or October, that's who's head I'm coming after."
Asked about Edwards' win over Diaz, he replied: "It was a good fight, good performance, I thought.
"Leon does what he does and he keeps asking for more money and more things, but he's not a finisher. He's not a fighter.
"He was winning happily and he wasn't willing to put himself in a risk to go out there and get those finishes.
"That's why I don't think he's in the position that he wants to be in, because he's not going out and fighting every second of every minute.
"So he's a very skilled guy, but he just doesn't have that grit and that meanness in him to go out there and beat up a top contender the way he should."
Despite his ruthless review, Masvidal appeared interested in facing Edwards - a shortlist that also included Nate and Nick Diaz.
'Gamebred' continued: "All of the above. Whoever's available October or November when I'm coming back, that's who's head I'm taking off. Whoever it is."
Masvidal is currently on a two-fight losing skid having lost a pair of fights to UFC welterweight champion Kamaru Usman.
He hasn't won a fight since beating Nate Diaz at UFC 244 back in November 2019.
Featured Image Credit: MacLife/PA
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