The man picked by President Obama to lead U.S. efforts against ISIS in Iraq and Syria will step down from the position this fall, sources told Fox News Tuesday.

Retired Marine Gen. John Allen, who has held the position as the president’s ISIS Czar for a year, is leaving over frustrations with the current U.S. policy in the Middle East as well as his wife being ill with an auto-immune disease, sources said.

Allen has been frustrated with U.S. policy for the past eight months, sources said, who added that he stayed in the position for six months longer than what he originally promised Secretary of State John Kerry. 

State Department officials told Bloomberg they were not ready to officially announce Allen’s departure, but he notified his superiors he will give up his job in early November.

Allen will be taking a job at the Brookings Institution when he leaves, sources told Fox News.

Last month, the nominee to lead the U.S. Marine Corps told the Senate Armed Services Committee said the war against ISIS was essentially a tie.

Lt. Gen. Robert Neller told Sen. John McCain, R-Ariz., he didn’t believe ISIS is winning or losing, but was in a “stalemate.”

A year after the U.S.-led air campaign began on Aug. 8, 2014, U.S. intelligence estimates ISIS has 20,000-30,000 fighters, the same number of fighters the CIA estimated last September.

Despite calling the war against ISIS a tie, Neller said in August he would not change the current strategy.

"I think we're doing what we need to do right now," he said.

Fox News’ Jennifer Griffin and Lucas Tomlinson contributed to this report.