Morata limped out of Chelsea's last game - the 1-0 defeat at home to Manchester City.
He reported for Spain duty despite his lack of fitness and doctors diagnosed the striker with a grade two hamstring tear.
The injury looked set to rule him out of action for a month to six weeks.
But Morata could yet make a speedy return.
The ex-Real Madrid man posted a video on his Instagram account this morning of him in the gym at Chelsea's training ground on an excercise bike.
Blues boss Antonio Conte will be desperate to get Morata back on the pitch as soon as possible.
Chelsea head to Selhurst Park on Saturday October 14 for a 3pm kick-off.
They then tackle Roma in the Champions League the following midweek.
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A home game with Watford in the Premier League follows next before another midweek tie - this time against Everton in the Carabao Cup.
Chelsea round-off the month with games against Bournemouth and the reverse tie away at Roma.
Conte's side host Manchester United in the first game of November before the next international break.