Sources: NFL fines Ben Roethlisberger $5,000 for wearing Apple Watch on Steelers' sideline

Ben Roethlisberger's first game back on the Pittsburgh Steelers' sideline since undergoing elbow surgery was painful -- in the wallet.

The NFL fined Roethlisberger $5,000 for a uniform violation because the star quarterback wore an Apple Watch when the Steelers hosted the Cincinnati Bengals on Monday night, sources told ESPN.

Roethlisberger is said to be "livid" about the fine and is appealing it, according to sources. But NFL rules ban all electric devices that transmit messaging.

Roethlisberger wore the Apple Watch on the sideline during the Monday Night Football game. His issue is that he never received any advance warning that he could be in violation, only a fine letter for wearing the device -- which he didn't even realize he had on, according to sources.

With Roethlisberger unable to use his right arm, his wife dressed him for the Monday night game and strapped the Apple Watch on his left wrist. Roethlisberger then assumed a position he rarely has in his NFL career -- standing in street clothes, including an Apple Watch, on the Steelers' sideline.