Stewart, who injured his leg Feb. 21 in an intrasquad game, said he felt good on Friday after playing in a Minor League game in which he did not play in the field. He has not played since, which prompted the Cubs to want another test as a precaution.
"The problem with MRIs is you can do them on everybody and you'll find something," Sveum said. "I feel great, but if you do an MRI on my body, it's not going to be very good."
• The Cubs assigned seven players to Minor League camp, including top prospects Javier Baez and Jorge Soler, and reduced the spring roster from 53 to 46 players.
Infielders Junior Lake and Josh Vitters were optioned to Triple-A Iowa, while infielder Christian Villanueva was optioned to Double-A Tennessee. Soler was optioned to Class A Daytona.
Three non-roster invitees were assigned to Minor League camp, including Baez, right-handed pitcher Barret Loux, and catcher Rafael Lopez.
The Cubs' spring roster consists of 24 pitchers (eight non-roster invitees), four catchers (one non-roster invitee), nine infielders (four non-roster invitees) and nine outfielders (three non-roster invitees).
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.