The 32-year-old has started twice for the Blues under Benitez, who was appointed interim boss in November, and was an unused substitute in Thursday night's 1-0 Europa League last-32 first-leg win at Sparta Prague despite being available following a knee injury.
Branislav Ivanovic and Gary Cahill played in central defence as last season's Champions League winners recorded back-to-back wins for the first time since December and kept a clean sheet for a second time in eight games.
"He (Terry) had a setback," Benitez said. "After he was fine again. He had no reaction in the next training session.
"It's a vicious circle: if he cannot play, he cannot improve his match fitness. We have to manage.
"In the meantime if Cahill and Ivanovic are doing well at least we can keep winning games."
Terry may yet return for Sunday's FA Cup fourth-round replay with Brentford.