Seville showed that a member of its first team had done coronavirus tests.
The anonymous player tested Sunday with the coaching staff and the rest of the first team, before the effects were unveiled on Monday.
The affected player is asymptomatic and self-isolated at home, the club promptly suspended educational sessions.
Since then, two tests have been carried out on the rest of the team and the technical staff.
If there are no further positive results, Seville plans to return to individual education – with “all the applicable measures” in place – on Thursday.
Sevilla finished their La Liga crusade with a 1-0 win over Valencia on 19 July for fourth place, but their Europa League commitments resume against Roma on 6 August.