New York Yankees left-hander CC Sabathia, on the disabled list with a right knee injury, will be out until at least July.

Sabathia received a stem cell treatment injection in the inflamed knee from Dr. James Andrews last week.

Yankees general manager Brian Cashman told the New York Post that the team was informed that if the process works, Sabathia would need at least six weeks of recovery time.

"Our dialogue with Andrews has been good and the small sample of stem cell procedures, the results are very successful," Cashman said. "But he has to be pain free before strengthening, so there is a way to go. Because he is a starter it will take longer. I have no idea how long it will be and if it will be successful. We are hoping it is six weeks to a major league return."

Sabathia was scheduled to stop using crutches Monday and begin pool therapy on Tuesday. The Yankees hope Sabathia can steadily build strength in the knee and then go through an abridged spring training before getting back on the mound.

The Yankees are also without starter Ivan Nova for the season after having Tommy John surgery. Michael Pineda, who has an injured lat, is throwing bullpen sessions. Cashman said Pineda's target return date is in the second week of June.

The Yankees' current rotation includes Masahiro Tanaka, Hiroki Kuroda, David Phelps, Vidal Nuno and Chase Whitley. Cashman said Adam Warren is the next pitcher the team would turn to if it has a rotation spot opening due to injury or performance.