City lost Fryatt on 36 minutes when, after lengthy treatment, he was stretchered off in a neck brace following a collision with Doncaster captain Brian Stock.
The Foxes medical team confirmed later Fryatt had been taken to hospital for scans on a neck injury and suspected broken jaw.
The first chance fell to Doncaster's James Hayter whose deflected shot bounced just wide of the target.
Dany N'Guessan hit back for City with an angled drive which flew narrowly wide.
The game was then held up for seven minutes as a posse of medical staff treated Fryatt as he laid motionless.
The lengthy interruption appeared to drain the game of any rhythm.
And at the end of a scrappy first half, City defender Jack Hobbs threatened briefly with a header from a cross by substitute Martyn Waghorn which ballooned harmlessly over the bar.
Paul Gallagher squandered one of the game's few chances on 47 minutes when he latched onto a Matty Oakley throughball and with only the keeper to beat, lifted a 12-yard shot over the bar.
Gallagher then released N'Guessan whose deft flick was blocked by the keeper's shin and the danger was cleared.
Rovers conjured up one of their rare threats on 62 minutes when James Coppinger drove straight at Chris Weale from 20 yards.
Billy Sharp then went close for Rovers with a low strike from 18 yards with the final significant action of the game coming soon after when Andy King headed an Oakley corner just over.
With two minutes to go, City manager Nigel Pearson threw on Steven Howard whose fate summed up the evening when he was shown a yellow card for dissent deep in stoppage time.