The diagnosis was a Grade 1 strain, the least severe. No timetable was set for his return, but Pollock said it "is not a significant injury by any means" and called the test results "good news."
Pollock and manager Torey Lovullo, speaking before Monday night's 7-3 win against the New York Mets, said the injury is less severe than the left groin strain that ended Pollock's season three weeks early last year.
Pollock was hurt running out a base hit in the 10th inning of Sunday's 6-4 loss to the Pittsburgh Pirates.
He said this injury feels "very similar" to the one he had in the other groin a year ago.
"I'm going to go after this thing," Pollock said. "The trainers are real positive about it, and so am I. I couldn't tell you which day but I'm sure I'll be feeling pretty good in the next couple of days and I'll be running around pretty soon."
Lovullo said Pollock will not be rushed back.
"When he returns," the manager said, "he's going to be 100 percent. He's going to be ahead of this injury and ready to contribute at the level he was contributing prior to the injury."
Pollock, an All-Star and Gold Glove recipient in 2015, missed nearly all of last season after breaking his elbow on a headfirst slide into home plate in an exhibition game two days before the opener.
He returned late in the season but played only 12 games before the groin injury.
Pollock has appeared in 37 games this season, batting .299 with 12 doubles, three triples and two home runs. He has 11 stolen bases and 11 RBIs.
Lovullo said Fuentes will share center-field duties with Gregor Blanco. Fuentes was in the lineup Monday night against the Mets, batting in Pollock's usual leadoff position. He went 1-for-5 in the win.
Fuentes was batting .376 for the Aces, fourth best in the Pacific Coast League. He was hitting .471 in his last 21 games.
He was signed by the Diamondbacks as a free agent in the offseason.
Fuentes, 26, has been in four organizations and hasn't yet fulfilled the promise he showed as a high draft pick. But Lovullo said some players mature more quickly than others and that Fuentes has all the tools needed to succeed in the majors.
Fuentes had appeared in 36 games over two major league seasons with San Diego and Kansas City, batting .243 with six RBIs.
In another move, the Diamondbacks designated right-hander Enrique Burgos for assignment.