Gibson made the announcement after Arizona's 7-5 win over the Chicago Cubs and said that an MRI showed the injury. Trumbo will fly home to Arizona to get a second opinion.
Trumbo has not played in the past two games.
Trumbo said he had a similar injury to his right foot in 2011, which took him 5 1/2 months to recover from.
He is batting .210 with seven home runs and 19 RBI in 21 games this season for the Diamondbacks, who are already 7.5 games behind the Los Angeles Dodgers in the National League West. JAFFE: After Albert Pujols, the next player to 500 homers could be years away