Stroman contract runs out in 2020, he is an unrestricted free agent in 2021.
I view him as an innings eater type, 3/4 starter type. He could actually do pretty well in the NL I think. But if he wants to be a Yankee I bet the Yanks will give him a look and try to get him at a bit of a discount. He will be 30 in 2021, so at best maybe he could net a 4 year contract.