[Mark Dexter]

According to ESPN.com, the ejection (and the ensuing fine) were for contacting the LJ:

Associated Press

NEW YORK -- Carolina wide receiver Steve Smith was fined $15,000 Wednesday for bumping an official during last Saturday's loss to Dallas.

Smith's fine was for "impermissible physical contact with a game official," NFL spokesman Michael Signora said. Smith was ejected in the third quarter against the Cowboys.

After Smith advanced a fumble and was tackled out of bounds by Terence Newman, he claimed he was hit a second time out of bounds. Smith immediately began yelling at line judge Mark Steinkerchner, then placed his arms around the official.

He was instantly called for a 15-yard unsportsmanlike penalty and ejected.

"I got hit out of bounds a little late, and as I was trying to get up, someone pushes me back down," Smith said after the game. "I grabbed the ref and said, 'Hey did you see that?'

"You're not supposed to touch a ref, I understand that. I wasn't doing it to put him down."

Smith, known for problems with his temper in the past, had behaved well this season.

"I wasn't trying to be demonstrative and all that stuff. I'm not trying to put my hands on the ref or get physical with the ref, that's not my style," Smith said. "It's my first time ever getting thrown out of a game."