Routledge has been loaned from Newcastle United to Queens Park Rangers until the end of the season and goes straight into Neil Warnock's squad to face City at Loftus Road on Sunday lunch-time in a game which is also live on Sky Sports 1 and 1HD.
Benni McCarthy might also feature if he is signed in time after scoring for QPR in a 2-9 friendly defeat against Tottenham as could Millwall's Danny Shittu who is also in talks with Neil Warnock.
Tickets for the game are on sale.