Some 50 Baltimore County firefighters were required to put out the blaze at Chris and Amber Ellis' home, The Baltimore Sun reported Monday.
The fire began after the couple's 16-year-old moved a car into the home's garage to clean. When he started the engine, it began smoking. He left the car in the garage, anticipating Chris Ellis would deal with the problem when he got home.
A neighbor called the fire department later after hearing an explosion in the garage and seeing flames.
The fire consumed much of the house and its contents, the family said.
McGregor told the Ellises they could have full use of his home while he and his wife, Cara, were in Sarasota, Fla., for spring training where he will coordinate rehabilitation programs for injured minor-league pitchers.
McGregor wasn't the only person to offer help. Another neighbor brought over a basket of clothes even before the fire was out.