Jeff Fisher’s tenure in Los Angeles didn’t last one full season.

The Rams fired Fisher on Monday and elevated special teams coordinator John Fassel to interim coach. The Rams are 4-9 heading into Thursday night’s game at NFC West-leading Seattle.

Fisher had been the team’s coach since 2012, and compiled a 31-45-1 record with the Rams. He oversaw the move from St. Louis to Los Angeles this past offseason.

The lack of success on the field, capped by a 42-14 home rout by Atlanta on Sunday, spelled the end for Fisher, who is tied with Dan Reeves for most regular-season losses in NFL history with 165. Fisher has the lowest winning percentage (.512) among coaches with 130-plus losses.

Los Angeles has scored a league-low 194 points this season.

“Making a decision such as this, especially during the season, is one of the most difficult in sports,” Rams owner Stan Kroenke said.

“I have great respect for Jeff as a coach, person, father and friend. He has worked tirelessly despite some challenging circumstances. He played an integral role in helping this team make history in returning the NFL to Los Angeles, and we always will be grateful for his commitment and dedication to our organization.”

Fisher, 58, went 147-126 as coach of the Houston Oilers/Tennessee Titans and helped that franchise in its relocation. He led the Titans to the 1999 AFC championship.

Long respected in league circles for his work on the NFL’s competition committee, Fisher never found success — or a franchise quarterback — with the Rams, who went 7-8-1, 7-9, 6-10 and 7-9 in his four full seasons.

They traded up for the first selection in this year’s draft and took California’s Jared Goff, but he rode the bench for much of the season behind journeyman Case Keenum as Los Angeles jumped out to a 3-1 start. Fisher finally turned to Goff in Week 11 and the Rams have dropped all four of his starts.

“Some of the performances the past few weeks have been a little bit more lopsided,” said Kevin Demoff, the Rams’ executive vice president.

“I think that’s what really tipped it. This is solely a performance-related issue. For the fans, for the players, for the coaches, for the organization we wanted to make sure games like (Sunday) didn’t happen again.”

Kroenke said in his statement that “this is the right time to make a change as our performance has not lived up to my or our fans’ expectations. We all are focused on improving as an organization and building a team that makes Los Angeles proud. Our mission is to celebrate a Super Bowl title with our fans in Los Angeles. Today is the first step to bringing us closer to that goal.”

Oddly, Kroenke gave Fisher a contract extension before the season, though it was not made public until recently.

Now, that extension looks more like a bonus to Fisher for his role in aiding the organization’s move to California than being any part of a plan for the team’s future.

Demoff would not commit on general manager Les Snead keeping his position, either.

“Starting today we are going to have a complete review of the entire organization. We sat down with Les, and again this team is not where it needs to be,” he said.

Fisher spoke to the team Monday before the firing was announced, and players reacted to his dismissal with a mix of guilt, frustration and anger.