"As with all other personnel moves, this is what we felt was in the best interest of the team at this time," Spagnuolo said in a statement. "We appreciate Richie's efforts and we wish him the very best."
A team spokesman said Spagnuolo would have more to say about the move Wednesday.
The Rams have other problems: Their other guard, Jacob Bell, is likely out for the rest of the season with a torn hamstring.
Incognito is a five-year veteran and has spent his entire career with the Rams after being drafted in the third round in 2005. He has frequently landed in trouble for playing long after the whistle and was named the dirtiest player in the NFL earlier this year by The Sporting News.
Incognito was benched after drawing two personal foul penalties for head-butting opponents in the first half on Sunday and then watched the second half from the bench with a poncho over his head. He was also yanked in the opener at Seattle after being whistled for two personal fouls.
The Rams (1-12) did their best to encourage Incognito, even naming him a weekly captain for one game in mid-October.
"I like Richie, I do. I'm trying to help," Spagnuolo said after Sunday's game. "I'm just trying to help."
Rookie quarterback Keith Null, who made his NFL debut as the starter last week, wouldn't say what aggravated Incognito against the Titans.
"I'm not going to go down that road with him and talk about that," Null said. "That's for you to ask him and him to deal with."
The Titans game was Incognito's second after missing four games with a sprained ligament in his right foot. He has played in 44 NFL games, all starts, in a career dotted with anger management issues dating to college when he was kicked off the team at Nebraska.
Before returning to the lineup, Incognito said if he were a gentlemanly lineman he'd probably be out of the NFL or perhaps playing for former Rams coach Jim Haslett in the United Football League. He didn't mind the "dirtiest player" recognition, noting that other players couldn't keep up with his "intensity level."
Last season, Incognito criticized the team's dwindling fan base, made an obscene gesture to a TV cameraman during practice and encouraged hecklers by cupping his hands to his ears while leaving the field after a loss.
Seahawks players criticized Incognito before a game in 2008, accusing him of jumping late onto piles, twisting ankles and scratching necks.
"You know, like the FBI's 20 Most Wanted? Yeah, he'd be on that list," Seahawks linebacker Julian Peterson said.
Incognito was All-Big 12 as a sophomore offensive tackle at Nebraska in 2003 but was suspended for repeated violations of team rules before the 2004 season and subsequently dismissed at Oregon later that year after attempting to transfer.