Ever Banega, Lucas Ocampos, Franco Vazquez and Luuk de Jong were seen congregating in a group of around 12 people in a since-deleted Instagram post uploaded by Banega's partner.
Sevilla, Spanish authorities and La Liga are likely to be wholly unimpressed at Ever Banega's wife posting a picture yesterday (soon deleted) of a gathering that included Ever Banega with Sevilla teammates Lucas Ocampos, Franco Vázquez and Luuk de Jong. pic.twitter.com/s3abAPkS6X— Yousef Teclab (@TeclabYousef) May 24, 2020
A maximum of 10 people are permitted at social gatherings in the city of Seville, which remains in the early stages of Spain's easing of lockdown measures.
LaLiga chiefs have implemented strict protocols to ensure players remain coronavirus free, meanwhile, in the hope of the league resuming in early June.
The actions of the Sevilla quartet may have put next month's restart in jeopardy, however, and they have each moved to express their regret following Saturday's gathering.
"I want to apologise for what happened yesterday," Banega said on Instagram. "It was a family get together with team-mates but unknowingly, we were wrong.
"For this, I want to apologise to our club, our fans and the society in general. It won't happen again.
"We only want to return to play as soon as possible."
Ocampos posted an apology of his own on social media, saying: "I want to say sorry and acknowledge that we have made a mistake, damaging the image of the club.
"For this reason, we can only apologise to the club, the team-mates and the coaching staff and to society in general.
"We guarantee that we have learned and that actions like this will not be repeated."
Fellow Argentinian Vazquez added: "Regarding what happened yesterday, I admit that it was a mistake. And as such the first thing is to apologise.
"We have failed everyone: team-mates, coaches, the club and LaLiga, but we have learned. It will not be repeated. Let football come back."
In the simultaneously posted messages, Dutch striker De Jong echoed his team-mate's sentiments.
"I want to apologise to everyone who may have been offended by what happened yesterday," he said.
"It will not happen again. We want the competition to return, we just want to play again."
Nearly 29,000 people have been confirmed to have died from coronavirus in Spain, making it the fourth worst-hit country in the world.