The 30-year-old Switzerland international suffered a hairline crack in his left middle finger during his side's midweek victory over Werder Bremen - before he was replaced at half-time by Max Green - and is questionable for the clash.
Benaglio saw a specialist on Wednesday and Hecking told his club's official website: "The finger is very swollen, it will be a race for Saturday."
However, Benaglio hopes to return to the first team as soon as possible, saying: "We now looking at it from day to day. I'll do anything to be back in goal as quickly as possible."
Meanwhile, Serbia Under-21 midfielder Slobodan Medojevic is still struggling with muscular problems and has been unable to train ahead of the Frankfurt clash.
Wolfsburg will be aiming to hold on to fifth this weekend after they moved up a place with Tuesday night's 3-1 victory away to Werder Bremen, as Borussia Monchengladbach dropped into the final Europa League qualifying spot following a 1-0 loss at Frankfurt.
Eintracht hope to make it three league victories in a week after Sunday's 5-2 demolition of Nurnberg was followed with a 1-0 win over Gladbach on Wednesday, as they look to pull further away from the relegation zone - where they sit eight points clear with seven matches remaining.
Germany defender Alexander Madlung returns to the club he spent seven seasons with before moving to Frankfurt in January and is anticipating a tough match.
He said: "I think if Wolfsburg want to stay on top, it is important that they win their home games.
"But, on the other hand, we need the points to give us even more breathing space and not to slip again.
"I think these are two different situations and on Saturday it remains to be seen what effect this will have."
Coach Armin Veh confirmed defender Marco Russ would be missing due to injury, while 19-year-old Marc-Oliver Kempf would take his place in the squad.