The defender impressed on loan at Brighton last season but Chelsea are keen to keep hold of the 20-year-old.
The Seagulls made a club-record £40m bid for Colwill earlier this month and the player remains open to a move to the AMEX Stadium.
But with a new long-term deal on the table at Stamford Bridge, Colwill will assess his options during pre-season.
Colwill was first offered a new Chelsea deal in January but opted against signing.
But now, his decision could be influenced by discussions with incoming boss Mauricio Pochettino who starts his tenure on Monday.
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With Chelsea well stocked in central defence, Colwill will seek assurances about his role under the Argentine.
Thiago Silva, Benoit Badiashile, Wesley Fofana and Trevoh Chalobah will all battle it out for a starting place next season.
Chelsea and Brighton are set to meet in the coming days to discuss a deal for Moises Caicedo to move to Stamford Bridge.
Caicedo is Chelsea's first-choice midfield target this summer but Brighton could push to include Colwill into a potential swap deal.
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Chelsea are not believed to be in favour of offloading their academy graduate and hope to integrate him into the first-team picture under Pochettino.
More will follow.
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