The facility will now be closed to players who were looking to train there over the weekend, but the team expects to resume practices Monday, Rutherford adds. The infected players were not identified.
Under Phase 2 of the NHL's return-to-play plan, players were permitted to begin working out in small groups at team facilities starting June 8, but the Blues waited until June 22.
The Tampa Bay Lightning were forced to shutter their training facility June 19 after three players tested positive. The venue was cleaned and re-opened five days later.
Fifteen of the 250 players who reported to training facilities for Phase 2 tested positive for the virus as of Monday. Another 11 players who did not report for voluntary workouts have also tested positive since the start of Phase 2.
Phase 3 of the NHL's return plan, which signifies the start of training camp, is set to begin July 10. However, the players have not yet voted to approve Phase 3 and Phase 4.