NFL referee Pete Morelli spoke a profanity into a live microphone Sunday as he asserted that a big hit could quickly change the complexion of an already defensive-heavy game during the Buffalo Bills' 16-0 win over the New England Patriots at Gillette Stadium.

The ref's utterance was not heard on the television broadcast because the game was in a timeout. But it was a mistake that will likely draw scrutiny from the image-conscious NFL office.

While speaking to another official during a third-quarter timeout, Morelli, a veteran NFL official in his 20th season, left his stadium microphone on. Those at the stadium heard him say: "Turned into a pretty good game. But one big hit, this s--- could explode."

The game did not hinge on a big play, much less a controversial late hit. The Bills were able to add only a field goal to their 13-0 halftime lead while keeping the Patriots' offense fully in check.

"Nothing was good enough," Patriots coach Bill Belichick said. "At any position, at any phase of the game, it just wasn't good enough."

In 2013, the league suspended umpire Roy Ellison for a profane and derogatory comment made to Washington Redskins offensive lineman Trent Williams.

Morelli's incident was not part of a confrontation, but the NFL has the authority to issue discipline if desired.

In the game, the Bills posted their first road shutout since Week 9 of 1990, when they blanked the Browns 42-0. Rex Ryan's win was his first in eight tries at New England in the regular season as a head coach.

"I think we have a disciplined team," Bills safety Robert Blanton said. "I think it's clear today we also had the better team."

Information from ESPN's Kevin Seifert, Mike Rodak, ESPN Stats & Information and The Associated Press was used in this report.