I doubt Fields envisions himself playing the "Taysom" role. If he did, he may could have stayed in Chicago. They are on record having interviewed a rookie draft prospect (Quincy Patterson, II) about playing the "Taysom" role. It appears that the Bears (as well as other teams) would like to have a player that can fill that role. Fields appears to have a similar skill set as Hill. That doesn't mean he has the mental desire to play that role, at least not with the Bears.
Now, we may see a number of designed plays from the Steelers that use Fields in run/pass option plays. That is about as far as you can expect to see Fields used in a comparable way to Taysom Hill. You won't see Fields playing special teams or blocking from the TE position. There's only 1 TH7.