Cal Ritchie.
I don’t think the Avs have anything else that would suffice. Utah doesn’t need picks or far off prospects. They aren’t trading a 6-5, two-way defender on a steep growth curve and bargain contract for magic beans.
Actually Ritchie for Kesselring is actually kind of fun. The Avs get a younger guy on a bargain deal they can plug into top four minutes who can be Manson’s eventual replacement at RHD. Utah gets a blue chip center prospect with a really exciting cerebral toolset who is close to NHL ready who can potentially fill their long-term 2C role.
In some ways I see Kesselring as a blueline version of what Hagel was when the Lightning got him (right down to the contract similarities), so the cost is going to be high.