Cresswell was returning after a three-match absence with a back injury, a problem which had restricted his appearances previously.
He appeared over it and fully fit but now comes this setback with manager Ronnie Moore estimating he could be out for as much as three months. "It's a big blow, obviously, and the lad has been unfortunate with one thing and another," said Moore.
It cast a shadow over an excellent Rotherham, performance in which Aldershot were unfortunate not to suffer a heavier defeat.
With Marcus Marshall carving through them on the right – frustrated left-back Jamie Vincent was sent off near the end after two bookings for fouls against him – Rotherham should have posted the sort of scoreline that one of their best displays of the season deserved.
Two outstanding saves by Jamie Young to deny Nick Fenton and Cresswell prevented Rotherham adding to their lead early in the second half.
They had gone in front five minutes before half-time courtesy of a 17th goal of the season from League Two's top scorer Adam Le Fondre, set up by Marshall's burst into the area.
Rotherham had a stroke of good luck 10 minutes before the goal when former Sheffield Wednesday winger Wade Small struck his penalty against a post.
Goalkeeper Andy Warrington, back after missing three games due to family reasons, made a splendid save from Ben Harding at the start of the second half before Rotherham took over.
Rotherham United: Warrington; Mullins, Cresswell (Ashworth 65), Fenton, Newey; Marshall, J Taylor, Law, Atkinson (Ellison 82); Le Fondre, R Taylor. Unused substitutes: Harrison, Bradley, Warne, Pope, Annerson.
Aldershot Town: Young; Herd, Morris, Jones, Vincent; Harding, Panther (Ngo Baheng 80), Guttridge; Small (Connolly 90), Morgan, Straker. Unused substitutes: Charles, Fortune, McGlashan, Randall, Clement.
Referee: G Sutton (Notts).
Man of the match: Marcus Marshall.
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