The 78-year-old has been working at the club's Carrington training base as a consultant to help the club's players. This is reportedly to help the squad adapt to manager Ruben Amorim's tactics as he focuses on the scientific principles behind the mechanics of an athlete's movement.
Marra has coached the likes of two-time decathlon Olympic champion Ashton Eaton, who twice broke the world record in the event, and heptathlon Olympic medalist Brianne Theisen.
Amorim’s tactics have not worked so far this campaign due to their high intensity.
Amorim discussed his tactics during the early stages of his tenure and explained that running and fitness will be key to it's success.
"It's impossible to win the Premier League without a team that doesn't run," Amorim said.
"You can do a starting line-up with the best players on the planet, without running they also won't win. We have to run like mad dogs, if not we won't win.
"The problem is can they cope with that? If they are used to it in training, they will do it in games.
"They can improve. You cannot be faster, but you can run more in training. They are professional athletes. Every coach has a different method of pressing."