Maybe as ambassador to somewhere, or something in Foreign Policy (maybe even UN Ambassador). But I can’t see why the Democrats would want to give away a domestic portfolio to a Republican when they’ve got such a larger domestic agenda the base wants to implement.
Well, Baker is moderate enough even on economy, to be an obstacle to most Democratic programs. In addition - a healthy dose of pragmatic moderate fiscal conservatism is even desirable for such Democratic administration. Otherwise it can spend a state into bancruptsy.