Terry's campaign has been severely disrupted by a knee injury and he has been unable to play consistently for Chelsea since returning to action in January. But Terry's decision to retire from England duty gave him two weeks in which to work on his fitness and break the "vicious circle" in which he had found himself trapped.
Chelsea's Barclays Premier League clash with Southampton on Saturday is the first of five games in 13 days, that includes quarter-final ties in the FA Cup and Europa League. "Every time when a player is injured he needs time to come back. This break is important," Benitez said.
"He was training with us every day and improving his fitness. We had just five players so we could pay more attention to everyone. He was positive and it was positive in terms of the time we had with him.
"It is just a question of how many games can you play? We will have four games in nine days. It is the same for everyone. You can't play all these games and be 100 per cent - not just him, everyone."
Chelsea face a gruelling schedule and Benitez admitted it will be impossible to field a full-strength side in every game because players cannot perform at their peak twice inside 48 hours.
But Benitez welcomed the packed calendar and selection headaches.
"The most difficult one will be these two games (coming up) because they are so close," Benitez said. "It is better to have this problem than be at home watching it on the telly because it means you are still competing."
Benitez is also hoping that Gary Cahill and Ramires will be available to face Saints.
"We have to ensure we have a competitive team against Southampton and a competitive team against United. We have to manage the squad carefully," he said.