The term "mismatch" undersells the disparity between these clubs. City's own website graphically depicts how it looks for Rovers.
City have reeled off seven straight wins in all competitions, beginning with their famous road win over Bayern Munich in Champions League play. Rovers have managed only one draw in their last six meetings with the Sky Blues, losing the other five times the sides have met.
Ladbrokes odds on the match reflect the disparity between the clubs. Even at home, Rovers are 9-to-1 to win and just 5-to-1 to earn a draw and a replay at the Etihad. City are 1-to-4 to go to Ewood Park and leave with a berth in the fourth round.
Which is why Pellegrini probably has mixed feelings about this match. A loss would be very embarrassing and deprive City of a chance to win one of the five trophies Pellegrini's bosses have demanded.
However, Pellegrini has openly complained of the demands City's schedule puts on his management of the club and the physical toll it takes on his players, per the Guardian.
Apparently Pellegrini's bosses put little stock in that grousing.
Riath Al-Samarrai of the Daily Mail reports that City are going to squeeze in a friendly on Jan. 14 against Al Ain in the United Arab Emirates—that is "two days after they play away at Newcastle United in the Barclays Premier League and four before they take on Cardiff."
As a result, some small part of Pellegrini might be tempted to dump this FA Cup match and engineer some free time for his club with Champions League knockout play and the Premier League endgame looming.
Of course, that will not happen—the stain of losing this match would be too great—but the XI Pellegrini will put out against Rovers is not going to be anything like the XI Pellegrini will select for the Jan. 12 Newcastle United match.
Predicted City XI at Blackburn Rovers: Costel Pantilimon; Dedryck Boyata, Matija Nastasic, Joleon Lescott, Gael Clichy; Samir Nasri, Jack Rodwell, Javi Garcia, James Milner, Jesus Navas; Edin Dzeko.
City will win this match. Whether Pellegrini really wants them to or not.