Reynolds, who did not allow a run through his first 19 appearances, has been on the disabled list with a strained left elbow since June 10.
He's thrown a handful of bullpen sessions and is scheduled for a few more before the D-backs take the next step.
"We have different options with him," Gibson said. "We could move him into a controlled environment, like the Instructional League. There's been no decision made yet."
Reynolds (0-2, 1.98) allowed nine earned runs over his final 9 2/3 innings, giving up his only two home runs of the season on June 6. He made his final appearance on June 9 against the Giants.
When Reynolds is right, he's shown the ability to get hitters out whether they are right-handed or left-handed. In fact, he had better success against right-handers this season.
Right-hander J.J. Putz (dislocated right little finger) is rehabbing in Arizona and is following a throwing program. He's getting closer to throwing a bullpen session, but Gibson feels uncomfortable with him doing so with his injured finger taped.