Philadelphia, PA -- (Sports Network) - Philadelphia Eagles defensive coordinator Jim Johnson has been granted an indefinite leave of absence as he continues his treatments for cancer.

The club announced in January that Johnson had been diagnosed with melanoma skin cancer. It was found in Johnson's spine, after he had experienced back pain and decreased mobility in weeks prior to the announcement. Johnson underwent treatment and had returned to the club as it gears up for the 2009 season, but now takes the leave as he continues to battle the disease.

"Jim and I agreed that he needs to concentrate all of his efforts on his recovery," said Eagles head coach Andy Reid. "His health is number one. He's struggling, but he's a tough guy and a true battler. I hope everyone will keep him in their thoughts and prayers during this period of time. We hope to have him back with the team as soon as possible."

The 67-year-old Johnson has overseen the defense for the entirety of Reid's head coaching tenure with Philadelphia. Secondary coach Sean McDermott will coach the defense in the interim.