Danny McGuire will skipper the Rhinos in Sinfield's absence and Liam Sutcliffe will take on the playmaking role as they look to bounce back from their first defeat of the season at Warrington last Friday.
"Kev's got some hamstring/neurol issue so he's stood down for a week to let that recover," McDermott said.
"He's a fantastic player for us and very influential so we will miss him but what we've got out there is good enough and Liam Sutcliffe certainly shows a lot of promise and has delivered in the past."
Jamie Peacock inspires Rhinos success
McDermott will also give a second appearance to prop Andy Yates after ruling Kylie Leuluai out with bicep and rib injuries and will make a late decision on whether to recall full-back Zak Hardaker after he was left out a week ago.
Wigan will be without three specialist front rowers, with Ryan Sutton joining Dom Crosby on the injured list and Ben Flower still suspended, and coach Shaun Wane must also cope without England winger Josh Charnley.
"It is a big blow because Josh is a good player but Dom Manfredi thinks it's great news," Wigan coach Shaun Wane said. "He gets a chance now and I'm a big fan of him. He can do things that Josh can't so I'm very comfortable with putting him in.
"He's unbelievably strong. He runs like a front rower. I know how difficult he is to handle because I arm-wrestle with him and he's a real tough character."
The Warriors returned to winning ways following their humiliation at Castleford but Wane was not impressed with their narrow victory over Hull and believes they have much to do yet to get their season on track.
"It was one win and it wasn't a great win," Wane said. "If we win our next four games I'll start to think we've turned the corner.
"I want to win again on Friday and put in a really tough performance.
"There's quite a bit of history between us and Leeds and a healthy respect. We've had some real tough games with them over the last few years. Leeds at Leeds is one of the toughest games you can get."
Elsewhere on Friday, Salford and Catalans Dragons will both be hoping to scratch a seven-game itch when they go to Castleford and Hull respectively.
The Red Devils have lost on each of their last seven trips to Castleford going back to 2004 while Hull have won their last seven home meetings with the Catalans, whose last win at the KC Stadium was in 2008.
Salford coach Iestyn Harris has the luxury of a full-strength squad as he seeks to extend his side's unbeaten run to four matches.
The return to fitness of Cory Paterson and Niall Evalds has given Harris a selection dilemma but two former Castleford favourites are guaranteed to face their old team-mates.
Rangi Chase was in the Red Devils team that lost 14-10 in the corresponding fixture last year but his cousin Weller Hauraki will be returning for the first time since his close-season move across the Pennines.
"There is no better place to play than the Jungle in front of all the fans," Hauraki said. "I will always look forward to going back to Castleford."
Salford will attempt to keep a close eye on Castleford winger Justin Carney, who has scored six tries in his four appearances against them.
The game at the KC Stadium will mean a reunion for Leon Pryce and his former Dragons half-back partner Scott Dureau, who is showing signs of recapturing his old form after two years of torment.
"Scotty's a really talented player," Pryce said. "He's had the worst of luck for the last two years and I'm really pleased for him as a person.
"He's had a brain tumour taken out and had other setbacks, including being sent back home to Australia, and that would have broken a lot of people."
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