The Citizens have failed to convert eight penalties from the start of the 2019/2020 season, according to TalkSPORT.
Sergio Aguero has been the side's main penalty taker but he has missed of the season while Kevin de Bruyne is also currently sidelined.
Ilkay Gundogan was removed from that duty after missing his penalty against Liverpool, as Rodri converted the spot-kick in the win over Tottenham Hotspur.
Rodri's spot-kick did not fill Guardiola with confidence, with the City manager expressing his concern for the situation.
"I would say I admire the courage to take the penalty but it was not a good penalty. I am not laughing, I am concerned about this.
"We will have a real specialist to take them with quality. We have to practice."