The NFL will conclude its official review of a head-butting play involving Colts linebacker Erik Walden this Monday, but the incident, from Thursday night's game, already has several league officials believing a suspension is warranted, sources said.

“See Antonio Smith (Houston) play from the preseason as relevant,” said one league source, a reference to a play in a preseason game in which the Texans defensive end yanked off the helmet of Richie Incognito and tossed it, earning a suspension for two preseason games plus the season opener.