Texts to sideline raise questions

— -- The NFL is investigating whether text messages were sent to the Cleveland Browns' sideline during games, league spokesman Michael Signora told ESPN.com Friday.

Texting would be a violation of the NFL's rules prohibiting electronic communication during games.

Signora did not elaborate except to say the league is looking into the matter.

Though it's not clear who sent the messages and who received them, a team source said the messages were subject of discussion among some players and coaches late in the season.

Cleveland.com originally reported the text messages were sent and said it was one issue in former offensive coordinator Kyle Shanahan leaving the team. He perceived it as interference from the front office regarding coaching decisions.

Though no texts have become public, the messages regarded personnel decisions and play calls, the source said.

The league's electronic devices rule states:

"Unless specifically permitted by league rules, the use of cellular phones, smartphones, tablet devices, computers, wearable electronic devices such as Google Glass, and other electronic equipment by coaches, players and other club personnel is prohibited in club-controlled areas including, but not limited to, sidelines and coaches' booths.

"These restrictions apply from ninety (90) minutes prior to kickoff through the end of the game, including halftime. Coaches, players, and other team personnel are permitted to use such electronic devices in the locker room prior to kickoff and are permitted to use league-issued Microsoft Surface tablets throughout game day for viewing coaches' still photos."