Everton's Baines set to face City
England full-back Baines was absent for Everton's 1-1 draw with West Ham in the FA Cup third round on Tuesday after picking up a knock in the 2-0 loss at Hull City on New Year's Day.
However, manager Martinez confirmed that the issue is not serious and he expects the 30-year-old to line up against the Premier League champions at Goodison Park.
"I don't expect Leighton to be out for more than two to three days," Martinez told Everton's official website.
"It would have been a huge, huge risk for him to play [against West Ham] after he picked up a knock against Hull.
"He wanted to play and to be involved but I hope now that he can be fit for the weekend."
Martinez, who confirmed that Sylvain Distin is to have a scan on a groin complaint, also revealed that captain Phil Jagielka has been playing through the pain barrier with an ankle injury.
"Phil came through really well," the Spaniard added.
"Phil has been carrying a dodgy ankle injury and sometimes that's restricted him a little bit."