If someone gives Tucker a megacontract it will be because they convinced themselves that (1) he would have been an ~8 WAR player the past two years until those seasons were derailed by injury, (2) those injuries were flukes and he's likely to be healthy moving forward, and (3) 1 and 2 mean he's more like a 6 WAR player moving forward not a 4 WAR player.
I don't even think it's that far fetched to think all of the above, but gambling that a player's health will improve as he gets older is a very dangerous game. For that reason, it's better to not stray too far away from the projections.