Manchester City defender Nicolas Otamendi will be assessed on Saturday as he attempts to prove his fitness for the derby clash with Manchester United.
City boss Manuel Pellegrini is already without captain Vincent Kompany for Sunday's Premier League encounter and will be desperately hoping his regular central defensive partner Otamendi will be declared fit after receiving a knock in Tuesday's Champions League draw with Dynamo Kiev.
"We'll see with Otamendi tomorrow - Nico is running but it's a risk if he takes another kick on the same leg. We'll assess him on Saturday," said the Chilean.
Belgium boss Marc Wilmots suggested on Friday that Kompany could miss up to eight weeks but Pellegrini was sticking by his initial assessment of a month's absence.
"Talking with the doctor, I think that Vincent has an injury in the other calf, not the same one as last time," Pellegrini added.
"We'll see in the way he'll improve - maybe in one month he can be ready. I think he could play again this season.
"It's a new injury in the other calf. It's high behind the knee, similar to the one that [Aleksandar] Kolarov had a month ago and he took three weeks to a month to recover so we'll see.
"It's important to see how he'll improve in the first few weeks. The first thing that we think is that within a month he can recover.
"Samir Nasri started working again with the whole squad yesterday. We hope that in the international break the three of them - Fabian Delph, Nasri and Kevin De Bruyne will play in a friendly with the under-21s."
City lie fourth in the Premier League table, 12 points behind Leicester City, albeit with a game in hand, but Pellegrini insists they will keep on fighting for the title.
He said: "In football when you have a mathematical chance you cannot think you cannot do it. It's a winning mentality - win the next game and then see which team has the most points.
"I think that a derby is always dangerous regardless of the position of both teams - if it's in the Premier League it's doubly dangerous."
United crashed out of the Europa League to Liverpool on Thursday to place more pressure on coach Louis van Gaal but Pellegrini says their cross-town rivals should not be underestimated.
"They have good players - United have a very good squad, it doesn't matter how they play, they're always a dangerous team," he said.
"It's a special game and I know the players treat it that way for the fans."