Gerard Pique claims Javier Mascherano turned down the opportunity to score his first Barcelona goal by refusing to take a penalty against Rayo Vallecano.
Barca set a new Spanish record by going 35 matches unbeaten in all competitions with a 5-1 rout on Wednesday, but not for the first time this season the Catalans fluffed their lines from 12 yards.
Luis Suarez was the guilty man on this occasion as he missed his spot-kick with Barca leading 3-1 in the second half, marking their seventh miss in 13 La Liga penalties this term while they have converted only nine of 18 in all competitions.
Earlier this month, fans set up an online petition for Mascherano - who has never scored for Barca since joining in 2010 - to take the next penalty.
Centre-back Pique revealed that Mascherano was asked to step up against Rayo, but the Argentina midfielder did not feel confident enough to do so.
"We told Mascherano to take the penalty kick but he did not have the confidence or has not wanted to shoot, but I asked," Pique said on Periscope.
Head coach Luis Enrique addressed Barca's poor penalty record after the game, but stated it was not a huge concern.
"We are not too good in that statistic, but in the end it was just an anecdote from this game," he said.
"We must improve in this aspect, but I have already said this is not something that worries me too much."