In a surprise move, David Westin, president of ABC News,  announced Monday night via e-mail that he will be stepping down from his post.

From the e-mail:

“As rewarding as I’ve found my time here, there are some other things I want to do professionally — things that I cannot explore while fulfilling my responsibilities here,” Westin, a lawyer, wrote in the e-mail, which had the subject line of “Transition.”

“I’m announcing my decision now so that I can pursue those possibilities, something I couldn’t do in fairness to all of you until I’d told you of my plans to step down. I have agreed to remain your leader through the end of the year.”