BOSS BACKS SMALLING FOR BIG GAME Sir Alex Ferguson will put his faith in Chris Smalling when he prepares his back four to face Manchester City in Saturday's blockbuster at Old Trafford. The 2010 signing from Fulham will partner Nemanja Vidic at the heart of United's defence as Rio Ferdinand's absence with a calf injury continues. Another centre-back option was lost in midweek when Jonny Evans, a starter in last Saturday's defeat at Wolves, injured his ankle while training with Northern Ireland. "Rio Ferdinand is out for a couple of weeks with a calf problem and Jonny Evans got injured training with Northern Ireland, so Chris Smalling will play," confirmed Sir Alex in Friday's pre-match press conference. "I'm sure young Chris will do well. He's been outstanding since coming to us." With Evans and Ferdinand the only new problems, Sir Alex feels his squad is in good shape for a fixture as important as Saturday's skirmish between local rivals currently placed first and third in the title race. "Tomorrow is a derby but it could also be a decisive game in terms of the championship for both teams and that makes it an interesting game for us," said the United boss. "You never get easy games in derby games but I'm going into the game with good confidence in the sense of our home form. I must say our home form has been outstanding and hopefully it works out that way tomorrow." More: Rio eyes derby win | It's all about the fans | Match Pack: Man City |