Wright-Phillips handed in a transfer request over the weekend and played no part in Sunday's 1-1 FA Cup draw at Notts County. But with Johnson set to spend three months on the sidelines after suffering a serious ankle ligament injury in training on Thursday, Mancini does not feel he has sufficient time to find a replacement if he allows Wright-Phillips to go.
"I can understand his position," said Mancini. "We haven't had any offers for Wright-Phillips at this moment but is difficult for Shaun to join another team now. We still have another 24 hours, so anything can happen but it (Johnson injury) probably affects it."
Johnson's absence is a major blow to City as he has been a regular contributor for the Blues this season, even if the former Middlesbrough man has not started as often as he would have liked. It is a problem for Fabio Capello too as Johnson will now miss the Euro 2012 qualifier with Wales at the Millennium Stadium on March 26.
"The injury is like the one Aleksandar Kolarov had earlier this season," said Mancini. "It is a big problem because we do not have another player like Adam."
At least skipper Carlos Tevez should be back for Wednesday's trip to Birmingham after sitting out the Meadow Lane encounter with a back injury.
In Tevez's absence, ?£27million new boy Edin Dzeko became the hero, scoring his first City goal 10 minutes from time to salvage a replay after Neal Bishop had nodded the hosts in front after an hour.
County boss Paul Ince was full of praise for his players and insisted they deserve credit for their enterprising performance.
"I know how these games work," said the former England skipper. "You are playing a lesser team and you think you can cruise through. I did it with Manchester United.
"It is not the case. Belief can overcome complacency. On days like this, the club from the lower echelons should be given the credit they deserve, not have people say City did not play well. We stopped them playing. It just felt like the clock stopped after we scored."