The talented midfielder appeared to take a dive while inside the Derry penalty area, and referee, Paul McLaughlin, promptly producing a second yellow card to the Dubliner.
Having already been cautioned in the 72nd minute, Fahey was booed off the Brandywell pitch, much to the delight of the home support.
In a game which saw clear-cut chances at an absolute premium, Rovers defenders David Webster and Conor Kenna produced superb last ditch tackles on either side of half-time.
Derry grew in confidence, but failed to breach a resolute Rovers defence to record yet another clean sheet and, in the end a draw was probably a fair result with both side happy.
However, both sides had one final chance at the death.
David O’Connor got his head to a Pat Cregg free during the latter stages, the ball just skimming the Derry bar.
And at the other end in the 93rd minute, Aaron Barry’s low drive screamed just wide of the Rovers upright.
Doherty; Sharkey, McBride. S. McEleney, Barry; Morrison (Curran, 77), Lowry, McNamee, Timlin; P. McEleney; Elding.
Hyland; Madden, Kenna, Webster, D. O’Connor; S. O’Connor (Miele, 81), Cregg, R. Brennan (McPhail, 63), G. Brennan; Fahey; Drennan.
P. McLaughlin (Monaghan).