James E. Rier, Jr., who has been head of the Maine Department of Education since February, has been placed on an indefinite medical leave of absence.

Though he will be on leave, Rier will remain in contact with department officials, said Samantha Warren, the department’s communications director, on Tuesday. She did not say what Rier’s condition is.

While Rier is out, the department’s chief academic officer, Rachelle Tome, will serve as acting commissioner. Warren said Tome was appointed acting commissioner by Gov. Paul LePage, effective Monday.

“The Commissioner is proud of the progress the Department has made under his leadership to advance key student-centered education reforms that will better prepare Maine kids for college and career success, and he and we look forward to him getting back to that important work in the coming weeks,” Warren wrote in an e-mail.

According to the DOE website, Rier served two terms on the State Board of Education, and was chair from 1997 to 2000. He joined the Department of Education in 2003, as the director of finance and operations.

As chief academic officer, Tome’s responsibilities include school improvement and accountability, according to the department website.