The Red Devils have endured a mixed season in all competitions, and have already lost manager Ole Gunnar Solskjaer.
With Michael Carrick in charge for the Thursday Premier League clash against Arsenal, and Ralf Rangnick set to take over as interim coach at the weekend, Sheringham knows there is a lot of upheaval around the team.
He believes they are a better team when Cavani starts, which has rarely been the case this term.
"United have got enough players like Greenwood, Rashford, Ronaldo, who all play off the number 10," Sheringham said.
"I just feel that Manchester United are such a better team when Cavani plays and he's the focal point of the team because he plays as a centre forward, as the number nine. That gives the whole team a focal point.
"When you have wingers playing at centre forward, they don't play that position how it should be played. They don't play with their back to the goal they still want to be running in the channel.
"Cavani has got everything as a centre forward, he holds the ball up, he wins headers, he runs the channels and he scores goals, so he does it naturally. When you don't have that, you don't have a focal point in the team."