Barcelona have confirmed to ESPN FC that Marlon Santos was left out of Wednesday's Copa del Rey game against Hercules because the club didn't want to risk making a similar error to the one which saw Real Madrid kicked out of the competition last season.
Madrid's decision to play Denis Cheryshev in their game against Cadiz breached the cup's rules as the Russian had carried over a suspension from the previous campaign, when he was on loan at Villarreal.
Marlon, 21, was not suspended for Barca's game in Alicante but the club did have doubts at the last minute about whether he would be eligible due to the delay in registering him at the start of the season after he arrived on loan from Fluminense.
The Blaugrana submitted the paperwork for the B team defender before the Aug. 31 deadline, but international clearance and visa problems meant he was not officially registered until a later date.
Barca, therefore, confused by the wording of the ruling, contacted the Spanish Football Federation [RFEF] on Tuesday to request confirmation of Marlon's availability.
However, by the morning of the game they had still not received an official response and took the precautionary decision to leave Marlon, who was expected to start the match, at home rather than expose themselves to the possibility of being thrown out of the Copa del Rey.
Because Marlon has already appeared in the Champions League and has been a substitute in La Liga, Barca don't expect there to be any issues in those competitions as they're governed by different rules.
