Saracens have abandoned their experiment of playing the former Great Britain rugby league skipper at blindside flanker and Sorrell believes his skills are better suited to inside centre.
"Andy has been getting the ball in his hands a lot more and with the skills he brings from rugby league that is exactly what you want," said the 29-year-old.
"He improved from the Leicester game to the Northampton game and that is in a week. He is a pretty quick learner.
"His key attributes are his distribution and his ability to work space for other people.
"In league it's basically two straight lines against one another so you have to pull the defenders out of position and put the ball into space.
"That's what 'Faz' has been able to do now that he is getting his hands on the ball a bit more."
Farrell should enjoy an extended run following the news that Ben Johnston requires groin surgery and will be out for a month.
Saracens have named an unchanged side following last Saturday's 35-15 victory over Northampton but Worcester have wielded the axe in the hope of securing their first victory of the season.
Half-backs James Brown and Matt Powell have been recalled, Aisea Havili is back on the right wing and prop Chris Horsman replaces Lee Fortey (dislocated shoulder), whose brother Chris takes over from hooker Ben Gotting.
Worcester are nine points adrift at the foot of the Premiership following eight successive league defeats.
Northampton head coach Paul Grayson insists team spirit remains high despite losing four of their last five Premiership matches.
Saints face London Irish at the Madejski Stadium with their fourth different centre combination - Robbie Kydd and Luke Myring - in as many weeks as injury, illness and the international program continue to bite at Franklin's Gardens.
"London Irish were high flyers last season and every club wants to sign off this November period on a high ahead of three weeks away from the league," said Grayson.
"Last week's game against Saracens was a hard loss but it did give opportunities to young players who will have learned a great deal from the experience. Team spirit is good and training has gone well this week."
In Sunday's remaining game, Wasps host Leicester in a battle for third place.