Sunday's Premier League match with Southampton is the first of nine matches in December for the Blues.
"Now is time for the squad," Mourinho said.
"The SSS week, everybody will have a chance."
Cole's absence in recent weeks - with Spain right-back Cesar Azpilicueta preferred - has been a surprise despite the England left-back's niggling rib problem.
"Ash will play for sure and will have the chance to show that he's fine," Mourinho added.
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