Real Madrid and Atletico Madrid coaches Zinedine Zidane and Diego Simeone both lamented the packed fixture schedule as their injury-hit sides prepare for La Liga action.
Real's game against Alaves on Saturday will be their third in a run of ten matches in 32 days. Zidane, who is without a host of players due to injury including captain Sergio Ramos and forward Karim Benzema, insisted there is a duty to look after player welfare.
"We're only at the start of the season. We want it to be a spectacle like it was before, but things have changed," he told a news conference on Friday, which came on the back of his side's win at Inter Milan in the Champions League at Inter Milan in the Champions League.
"What matters to me is looking after the players. When one of my players is injured, I suffer for them. Right now, with all the games that we have coming thick and fast, we need to take care."
In addition to Ramos and Benzema, Zidane confirmed he would be missing midfielder Federico Valverde, as well as defenders Alvaro Odriozola and Dani Carvajal. Luka Jovic will also be absent following a positive Covid-19 test.
Atletico, who played in Europe on Wednesday night, visit Valencia on Saturday before hosting reigning champions Bayern Munich in a must-win Champions League game on Tuesday.
Simeone's side will be without forward Luis Suarez and midfielder Lucas Torreira, who continue to isolate following positive Covid-19 tests.
Manu Sanchez, Hector Herrera, Diego Costa and Sime Vrsaljko will also miss the game due to injury problems, leading the Argentine to suggest La Liga's 25-man squad limit is insufficient.
"Given the current circumstances, we'd need a squad of 35 (to cope with all the games). This is the schedule that there is, it's all squeezed in and we can't do anything about that," he told a news conference.
"There's the national team, back-to-back games, Champions League, more national team games; they're things that you see at the start of the season and know things will be tough around those times."
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Goalkeeper Jan Oblak did not train with his team-mates on Friday, however, local media reports suggest it was purely precautionary and that he will be fit to play.
Atletico are second in the Liga standings, three points behind table-toppers Real Sociedad having played two games fewer. Valencia, who have fared well under new coach Javi Gracia despite losing a number of first-team players in the transfer window, have not beaten Atletico in the league since 2014.