Gayle was replaced early in the first half of Monday’s 2-0 win over Aston Villa at St. James’ Park with what appeared to be a recurrence of the hamstring injury that had kept him out of action for a month.
But Benitez said that his number nine had responded well to initial tests, but wouldn’t be drawn on how long the problem would keep the 26-year-old out for.
“We don’t have a timescale, because he is doing really well. We are quite pleased with the situation now in terms of time, but we cannot say how long,” said Benitez.
“He is not training, but all the tests that we have done are quite positive, so I think it’s a question of his confidence more than anything.
“It’s just a question for me now of confidence – he has to feel that he is fine and play with confidence, and in the end that’s the most important thing.
“To lose your top scorer is not ideal, and you miss something. But Mitrovic and Murphy, when they have had to play, have done really well, even Gouffran or Ayoze. We can cope with that, but it will be better to have him on the pitch and competing with the others.
“But I’m quite positive, because I think he is doing well.”
Bristol City are the visitors to St. James’ Park on Saturday (3pm kick-off).
And despite the Robins’ lowly position in the Sky Bet Championship table and the absence of their on-loan goal-getter Tammy Abraham, Benitez is expecting a stern test from Lee Johnson’s side.
“We know that it will be difficult. They are well organised, they work hard, so even though we have lost Gayle and they lost Abraham, they still have good players,” he said. “They’re a team who are working very hard.
“When we played against them in the first part of the season they were a very, good team. You can see they have the same structure, the same organisation, and maybe they have been a bit unlucky with some goals.
“In terms of how difficult it will be, it will be a tough game, as always.”
Benitez added: “We have had some games that, on paper, could be easy, but we have also seen that the Championship is so difficult. Any game can go against you if you don’t do the right thing. You have to be sure that you are ready, prepared and try to do your best.
“You can lose games that nobody is expecting, but you can win games that are very difficult. I’m confident that the team is doing well and has the right mentality, and hopefully we can show this tomorrow on the pitch.”
