The team said all players would go into a 10-day quarantine.
Kashiwa reported its first positive test – a player - on November 1 and announced the positive case for Nelsinho and one staff member two days later.
Cases of coronavirus infections in Michael Olunga’s Kashiwa Reysol have risen to 14, reports say.
According to Yahoo! Japan, two new players and eight staff members have returned positive tests from PCR (polymerase chain reaction) tests done on November 3.