I understand the concern regarding signing a 28-year-old player, who has a falling curve and has been frequently injured recently. But he is not championship quality, he is better than that.
Physically he is a beast, and in his best days he can make life difficult for all teams. He is also relatively good with the ball. In addition, he can play in several positions offensively. He has a couple of good years left, and signing him will strengthen the squad.
It is possible there are better alternatives out there, but we need players who can fill the role of DCL and Richarlison if they are injured / suspended. King can definitely do a great job.
I think he's worth the chance.