The 19-year-old centre-back spent last season on loan at Huddersfield and was hugely impressive in the Championship.
He still has three years left on his contract but his long-term future at Chelsea is under the scanner in the ongoing transfer window.
Chelsea are on the verge of signing Kalidou Koulibaly and are also working on deals to sign Presnel Kimpembe and Nathan Ake ahead of the new season.
And it has been claimed that Colwill is now actively looking to move on from Chelsea in the ongoing transfer window.
With Chelsea expected to sign three defenders, the teenager sees no way into the first team plans of manager Thomas Tuchel.
Leicester City and Southampton are both keen to take Colwill away from Stamford Bridge.
He is also attracting interest from Fulham.
There are suggestions that Colwill could even push for a permanent move away from Stamford Bridge this summer.
The defender is not sure that he has a long-term future at the club with Chelsea set to heavily invest in centre-backs.
