Gary Neville denied there being an oversight in Valencia's signing of Denis Cheryshev and Guilherme Siqueira, despite only one being eligible for their Europa League campaign.
Valencia finished third behind Zenit and Genk in their Champions League group and will subsequently feature in Europe's second-tier competition, where Rapid Vienna await in the round of 32.
In the final two days of the previous transfer window, the club signed Siqueira from Atletico Madrid and loaned Cheryshev from Real Madrid until the end of the season.
However, only one of the duo is eligible to represent Valencia in the Europa League having already featured in Champions League action this season at their previous clubs, but Neville insists the club were aware of the situation.
"It's not my decision, it's not the decision of Valencia, it's a regulation that's set by UEFA and we have to select one," the 40-year-old coach said.
"It's not about choosing one or the other. I've made my decision and I've spoken with the player involved, it's not a secret.
"We need both players because were in Copa, Europa League and obviously we've still a lot of La Liga matches still to play.
"It could be that you want to make a negative situation of the fact that I've had to select one player of the two but it's purely a regulation of UEFA and it's not a mistake of the club.
"We were fully aware of the situation that if we signed these two players this could happen. It's a situation that all players will get football in this period of time but I agree it's disappointing to have to make selections like this."