Tevez is now back with City after a lengthy dispute during which he spent more than three months in his native Argentina without the club's permission.
The striker apologised for his conduct earlier this week and manager Roberto Mancini has said he no longer has a problem with the 28-year-old.
That has opened up the possibility of a first-team return for Tevez, once match-fit, during the Barclays Premier League leaders' final title push - but not all supporters have welcomed that prospect.
Richards said: "It is hard - it will be 50-50. It is not really for me to comment.
"If he can get his head down and we end up winning the Premier League and he plays a massive part in that, I am sure everyone will forgive him.
"If he doesn't, it could be the opposite. It is mixed feelings [for fans] really, but as a player I am happy to have him back because he is an outstanding player."
Tevez met Mancini on Thursday for the first time since returning to the club.
The Argentinian will continue to work to his own fitness programme but was involved in a training with the senior squad.
Mancini has predicted he could be ready for action in two or three weeks' time.
His availability will give City, two points clear with 13 games remaining, the option of their top scorer for the past two seasons as they chase a first league crown since 1968.
Richards, whose own form has earned him an England recall, said: "Tevez was outstanding last season. He was inspirational.
"He was our captain and a leader. He was unbelievable on the ball but also off it, he worked so hard.
"He is a nightmare to play against and to have that in the team would be really good for us."
Tevez has not played for City since September but his previous record is impressive, having scored 52 goals in 91 games for the club.
He will now link up with a strike trio of Sergio Aguero, Edin Dzeko and Mario Balotelli, who between them have scored 49 times this season.
Richards, 23, expects competition for places up front to be fierce.
He said: "I am sure the other strikers will be thinking we have done well until this point.
"I am sure they will sort it out but it is a massive boost.
"He is still a quality player. He is just lacking fitness.
"Games are all he needs now. He has just had a long holiday. He is a better golfer."