He might not even be the backup.

Rex Ryan decided to bench Sanchez on Tuesday in favor of Greg McElroy after the fourth-year quarterback had another miserable performance in a 14-10 loss at Tennessee on Monday night that eliminated New York from playoff contention.

“I think it’s best for our team, and for this game,” Ryan said during a conference call.

So, it’ll be McElroy under center for his first NFL start when the Jets (6-8) play the San Diego Chargers at home Sunday. Ryan hasn’t decided whether Sanchez or Tim Tebow — listed as the No. 2 quarterback — will be the backup.

While Sanchez blew the second chance Ryan gave him a few weeks ago, Tebow was leapfrogged by a third-stringer, fueling speculation that the team has little confidence in him as a quarterback.

“I have to look at what I think is the best for the team and not necessarily the individual,” Ryan said. “I’ll say this about Tim and I’ve always said it: I know he wants to help this team be successful in the worst way and there’s no doubt about that.”

Sanchez threw four interceptions Monday night and wasn’t able to handle a low snap with the game on the line, ending the Jets’ hopes to get back into the postseason.

Things got worse after the game for Sanchez, who received a series of death threats from one disgruntled fan on Twitter. League spokesman Greg Aiello said the NFL’s security staff was aware of the man’s threats and was working with the Jets to assist on the matter. The team declined comment through a spokesman.

Ryan said after the loss that he wasn’t ready to decide who would start against the Chargers, but told Sanchez he would be making a change at quarterback by going with either McElroy or Tebow.

“He respected my decision,” Ryan said. “That’s not easy, that’s for sure.”

After talking to his staff and members of the organization Tuesday, Ryan chose McElroy.

“This is my opinion, and I do believe that it’s best for our team that Greg is our quarterback,” Ryan insisted. “I’m the guy that’s making this decision. Every decision I make is based on what I believe is the best decision for the team.”

But Ryan was vague in his answers to why he selected McElroy above Tebow, choosing after being asked several times to not go into detail about what specifically factored into the decision.

“I can answer this question a million ways, frontward, backward, sideways, anything else,” Ryan said. “It’s my decision and I based it on a gut feeling or whatever.”

McElroy, a seventh-round pick last year out of Alabama, helped lead the Jets to a 7-6 win over Arizona on Dec. 2 when Ryan pulled Sanchez from that game late in the third quarter. McElroy had modest numbers — 5 of 7 for 29 yards — but threw for the only touchdown of the game, and nearly led another scoring drive as the Jets ran out the clock.

Ryan decided to stick with Sanchez after that game, saying that the one-time face of the franchise gave the Jets their best chance at winning as they remained in the playoff hunt.

But Sanchez struggled in a 17-10 win over Jacksonville and again even more in the loss to Tennessee. McElroy, who gave the Jets a huge spark in his first NFL action, was inactive for both games. That hurt New York on Monday night when Ryan was unable to turn to McElroy since he was not in uniform for the game. Instead, Ryan went to Tebow for one series — which had been part of the game plan — but it was unproductive and Sanchez came back in for the next offensive possession.

Sanchez leads the league with 24 turnovers, including 17 interceptions, and has turned the ball over 50 times since the start of last season. His future with the team is uncertain because he signed a contract extension with New York in March that included $8.25 million in guaranteed money for next season.

Ryan would not commit to Sanchez beyond this season, and wouldn’t discuss what the depth chart will look like.

“We have two games left and that’s where my focus is going to be,” he said. “What’s past that will be determined later.”

Sanchez was regularly booed during home games this season, falling out of favor with the fans who were excited when the Jets traded up to take him with the fifth overall pick in the 2009 draft.

“Has he had better days than (Monday night)? Absolutely,” Ryan said.

There certainly were some good moments for the former Southern California star, particularly in helping lead New York to the AFC championship game in each of his first two seasons, but he failed to take the next step in his development.

While his frequent mistakes in reading defenses and miscalculating throws are a huge reason for his struggles, Sanchez also wasn’t helped by a constantly changing cast around him. Several of the team’s top offensive players — Thomas Jones, Leon Washington, Jerricho Cotchery, Brad Smith, LaDainian Tomlinson, Plaxico Burress, Alan Faneca and Damien Woody — have all been released, traded or allowed to become free agents since Sanchez’s rookie season. He is also working with his second offensive coordinator in Tony Sparano after an up-and-down three seasons with Brian Schottenheimer.

Tebow, acquired from Denver in March, has had a minor role in the offense after being expected to play a major part. He is recovering from two broken ribs that sidelined him for three games, but returned Monday night and had little impact. It would seem unlikely that Tebow, who helped lead the Broncos to the playoffs last season, will be back next season.

When Tebow arrived in New York, he often said he was “excited to be a Jet,” but there’s little doubt that he no longer feels that way. He has done his best to hide his frustration throughout the season, especially when the wildcat-style offense was talked up by Ryan and Sparano as a highlight of the offense.

Tebow has instead just been a spare part on an offense that ranks 30th in the NFL. He is 6 of 8 passing for 39 yards, and has run 32 times for 102 yards — playing a more significant role as the personal punt protector on special teams.

“People can speculate anything they want,” Ryan said. Obviously, as a football team, we’re 6-8 and nobody’s happy about that and ultimately, I’m the one accountable.”