Barcelona defender Gerard Pique was loudly whistled at Spain training on Monday, a day after he said he was open to leaving the national team because of the political climate in Catalonia.
The 2010 World Cup winner was jeered by fans upon his entrance onto the training pitch in Las Rozas, outside Madrid, while others raised inflammatory banners directed at the defender.
Police and security staffers removed some of the signs, one of which read: "Pique do not go, I want you to be kicked out. You make me sick." Others simply said: "Pique out."
El Pais reported that about 200 of the 1,000 fans in attendance sang out during the light training, which only lasted about 20 minutes before Pique and the majority of players withdrew.
Barcelona's 3-0 defeat of Las Palmas was played behind closed doors on Sunday after Spanish police attempted to shut down Catalonia's referendum on its independence. Officials said more than 890 civilians and some 430 members of the police force were injured.
Pique, 30, was among those who did vote in the referendum -- which has been deemed illegal by the Spanish government -- after he had promoted the people's right to self-determination earlier in the week via social media.
That had drawn criticism from some sections of the sports press in the country, and his continued presence with the Spanish national team has been called into question.
Earlier on Monday, Pique shared a video on Twitter of a violent clash between Spanish police and protesters and criticised the officers, saying: "They acted with professionalism and with a fair and even manner."
Following Sunday's match, a tearful Pique -- who called the game the worst experience of his professional career -- told reporters he was prepared to quit national team duty with Spain if his presence was deemed a problem by coach Julen Lopetegui.
"If anyone believes I am a problem for the federation, I will step aside from the national team before the World Cup [in Russia next summer]," Pique said.
"Going with the national team is not a competition in patriotism, it's about trying to play the best you possibly can."
Pique has won 91 caps for Spain and was a member of the sides which won the 2010 World Cup and Euro 2012.
Spain, who lead Group G, will wrap up their World Cup qualifying campaign with matches against Albania and Israel on Oct. 6 and 9, respectively.
Earlier on Monday, Spain announced that Chelsea's Alvaro Morata, Andres Iniesta and Dani Carvajal would be unavailable through injury.
They were replaced on the squad by Real Sociedad's Alvaro Odriozola, Las Palmas' Jonathan Viera and Athletic Bilbao's Aritz Aduriz.
ESPN FC Barcelona correspondent Sam Marsden contributed to this report