The three-time premiership player was originally expected to miss 8-10 weeks after surgery following Geelong’s win over the Gold Coast in round three.
However, the infection, which will keep him in hospital for two days, is expected to delay his return for an extra two weeks.
General Manager of football Steve Hocking said that despite the minor setback, the club has been pleased with how Bartel’s rehabilitation is progressing.
“Jimmy experienced some soreness in his knee on Friday and the medical staff took quick action and identified the issue,” Hocking said.
“Jimmy has had the knee washed out and he will spend a few days in hospital receiving antibiotics. His return will be slightly delayed but we are pleased with how the injury itself is healing and if not for the infection Jimmy would have been on schedule to return.”