Shortstop Addison Russell underwent an MRI exam on his right foot Thursday after being examined by Cubs orthopedic physician Stephen Gryzlo. The MRI revealed Russell re-aggravated plantar fasciitis in his right foot and will be out for at least three more weeks. He had been planning to return this week but aggravated the injury while on rehab at Triple-A Iowa. Mike Freeman, a 30-year-old infielder the Cubs signed when the Dodgers designated him for assignment three weeks ago, is expected to be called up from Triple-A Iowa on Friday when rosters expand. Freeman is a career .123 hitter in 41 major-league games and was hitting .306 at three Triple-A stops this year. With Russell's return date unknown, Freeman could be Javier Baez's primary backup at short.