Manager Kirk Gibson said Trumbo, who was placed on the 15-day disabled list Thursday retroactive to April 22, will get a second opinion from Dr. Michael Lee in Arizona before a timetable for his return is determined. An MRI taken Wednesday revealed the injury after an X-ray showed no structural damage.
The MRI also revealed some plantar fasciitis, which Trumbo had been dealing with since spring training. Trumbo wasn't sure how the stress fracture developed but thought he was overcompensating due to the plantar fasciitis.
Trumbo is hitting .210, although he was tied for the National League lead with seven home runs and was second with 19 RBIs before Wednesday's game against the Chicago Cubs.
The Diamondbacks recalled Roger Kieschnick from Triple-A Reno on Thursday to take Trumbo's place on the roster. Kieschnick hit .281 with three homers and eight RBIs in 18 games at Reno this season.
Trumbo said he first experienced pain relating to the stress fracture when he ran to the outfield in the bottom of the seventh inning Monday against the Cubs. But couldn't pinpoint what specifically caused the injury.
"The plantar (fasciitis) at times has been pretty bad but manageable," Trumbo said. "That's what you have to do. You've got to earn a living and play. This was to the point where I severely had to compensate running-wise to the point where I probably wouldn't be much of an asset on either side."
Trumbo suffered a stress fracture to his right foot at the end of the 2011 season and needed 5½ months to heal. He does not expect to need as much recovery time with this injury.
The Associated Press contributed to this report.