The France international is back in training despite having been ruled out for the rest of the season with a long-term hamstring problem, but manager Alan Pardew has indicated that he will be involved against the Portuguese league leaders.
However, central defender Steven Taylor is out with a knee injury and joins Fabricio Coloccini (back), Davide Santon and Cheick Tiote (both hamstring) and the ineligible Mathieu Debuchy and Yoan Gouffran on the sidelines.
Benfica coach Jorge Jesus has warned there is no room for complacency.
The Portuguese league leaders will run out to face Newcastle at St James' Park defending a 3-1 first-leg lead and knowing they have one foot in the last four.
However, Jesus is wary of the threat posed by the Magpies, who took the lead at the Estadio da Luz and twice hit the post before finally succumbing to a second-half onslaught.
Asked if his side had done enough in Lisbon to secure their passage, Jesus said: "We did enough - we scored three goals and Newcastle scored one.
"But everything is still open, of course, and they [Newcastle] still believe they can go through as well so everything will be decided tomorrow."
Benfica are unbeaten in 31 games in all competitions.