Former Watford boss Lewington is expected to tie up a move to Fulham within days.
Fulham boss Chris Coleman wants Lewington's coaching expertise and is keen to make him his first signing for next season.
Lewington, who has been out of work since being by axed by Watford in March, started his managerial career at Craven Cottage in 1986.
The former Chelsea player has also managed Crystal Palace and Brentford.