Chicago Cubs first baseman Anthony Rizzo will undergo an MRI on his back, with the development coming after a batting practice session that was held on Sunday.
"Once he cooled down, some of that stiffness came back," Cubs manager David Ross said Tuesday, per ESPN's Jesse Rogers. "He's still day-to-day. Going to get some tests run and see where he's at."
Rogers noted Rizzo has missed approximately a week's worth of practice because of the injury.
Rizzo has proved to be fairly durable through the years, never making fewer than 140 appearances in a single season since his first full year in the majors back in 2013.