The former Sporting CP player suffered a thigh muscle strain in training on January 30 which he has been struggling with since his arrival at the St James' Park.
Though he trained with the club for the first time on Wednesday, the gaffer has stated why the forward failed to make his bow.
“He was fine, but he was still feeling it a little bit,” Benitez was quoted as saying by Shields Gazette.
Newcastle now have a two-week break ahead of their next league clash with Bournemouth on February 24 and the former Liverpool boss is hoping that the forward will be fit for the tie at the Vitality Stadium.
"It was a case of waiting because we have 15 days now before the next game so we can keep working with him.”