Man, thinking more about this, such a move might send the 'Muth truthers out there off a cliff. I remember offering a future 1st for 'Muth at one point in a TE-P league a couple of years back and not only being rejected, but in such a way that questioned my sanity for even offering.
Anyway, hopefully this is smoke with no fire and Jonnu stays with the Dolphins.
Dude was literally their only pro-bowler last year.
Jonnu is a tough call, because he's a pretty limited TE. He's only good against zone defenses, when he's schemed touches. Its why he didn't work out in NE at all. He's not a good route runner, and most offenses aren't gonna accommodate that like Miami did last year, and its arguable it was to their detriment, and they should have been scheming more to Hill/Waddle, even if it was shorter stuff.
I will say it could speak to what the Steelers want in the position though. Jonnu is WAY better than Muth after the catch. Muth is a better blocker, and 3 years younger so a swap could make sense for both sides. Darnell Washington also is a bit of a RAC guy, so maybe that's more the direction they want to go at the position, but they also just extended Freiermuth so...?