Colwill withdrew from the England squad earlier this month due to a shoulder injury, while Gusto pulled out of the France Under-21s squad last week with a knee problem. However, both players have trained with Chelsea this week and could therefore be available on Saturday.
Christopher Nkunku (knee) and Romeo Lavia (ankle) have also been spotted on the training field, but Saturday's game may come too soon for the duo, who are yet to make their competitive debuts for the Blues since joining the club in the summer.
Meanwhile, Conor Gallagher should be fit to feature against Newcastle despite arriving at the England camp with a minor ankle issue; the midfielder played the first 45 minutes against Malta before watching on as an unused substitute versus North Macedonia.
However, Mauricio Pochettino's side will have to cope without Ben Chilwell (hamstring), Wesley Fofana, Carney Chukwuemeka (both knee), Trevoh Chalobah (thigh) and Marcus Bettinelli (unspecified) as they continue to recover from injury.
Reece James rejected an England call-up this month to concentrate on building up his fitness, and the Chelsea captain is in contention to start in defence on Saturday alongside Axel Disasi, Thiago Silva and either Colwill – if fit – or Marc Cucurella.
Enzo Fernandez, Moises Caicedo and Gallagher are the most likely trio to start in midfield, while Cole Palmer and Raheem Sterling are expected to retain their places in the final third alongside central striker Nicolas Jackson, although Mykhaylo Mudryk will be hoping to force his way into the first XI.
Chelsea possible starting lineup: Sanchez; James, Disasi, Silva, Cucurella; Fernandez, Caicedo, Gallagher; Palmer, Jackson, SterlingNo Data Analysis info