No. They can't cut him but he's a free agent after this season. If he signs with another team, assuming he gets a lucrative deal, they could get a 2020 draft pick, likely to be a 4th (not a third).
But people are ignoring his age, which doesn't always play well in free agency. I'm not convinced he gets a top deal. Especially if his numbers suffer with the eagles (and they might, considering midseason WR acquisitions historically take some time to adjust).
Also, even if it's a 4th round compensation, they have to wait 2 years for it. And people keep forgetting that those comp picks are at the end of the rounds so a 4th is essentially an early 5th. It's a far cry from the 2019 3rd they gave up.