Chelsea are looking to build a squad that can potentially cope with a 75-80-game season, including next summer’s Club World Cup.
They have qualified for the Europa Conference League and are aware that their squad will be severely tested by a congested fixture list.
Chelsea are well stocked for midfielders, with Moises Caicedo, Enzo, Conor Gallagher, Romeo Lavia and Lesley Ugochukwu already competing for first-team places, and Andre Santos hoping to get a chance in pre-season to impress.
Interest in Dewsbury-Hall and Gray will only increase speculation over the future of Gallagher, who is currently on England duty and has attracted interest from Aston Villa, Tottenham Hotspur and Atletico Madrid.
The Blues have also signed 18-year-old attacking midfielder Omari Kellyman from Villa and have highly-rated Carney Chukwuemeka, who can fill a number of positions, at the club.
Cesare Casadei, who played on loan for Maresca at Leicester last season, has attracted interest from European clubs and may be allowed to leave Chelsea this summer.
Chelsea are signing 18-year-old forward Marc Guiu from Barcelona and are still in the market to sign another striker, a right-footed winger and a left-back.