Arenado (chest) is not in the Diamondbacks' starting lineup against the Red Sox on Monday.
Manager Torey Lovullo said that an MRI showed a "small signal" in Arenado's left intercostal, per Jody Jackson of DBacks.tv. However, Arenado will be available off the bench Monday, and the expecation is that he will avoid the injured list. Jose Fernandez -- who was recalled from Triple-A Reno on Monday after Ketel Marte (not injury related) was placed on the restricted list -- will start at third base and bat seventh.