In the scripting reference for Animator.Play the description simply says “See IAnimatorControllerPlayable.Play.” and has a link to https://docs.unity3d.com/ScriptReference/Animations.IAnimatorControllerPlayable.Play.html which is a 404 error.
Is that information accessible anywhere?
Try this Unity - Scripting API: Experimental.Director.IAnimatorControllerPlayable.Play This is from 5.6.0. though and is “Experimental” https://docs.unity3d.com/Manual/Experimental.html.