"I have to get this decision right," Ryan said, "and I believe I have."
Sanchez was pulled late in the third quarter, and McElroy came in and led the Jets to the only touchdown of the game on his first NFL drive and helped New York to a 7-6 victory. Sanchez was 10 of 21 for 97 and three interceptions, while McElroy was 5 of 7 for 29 yards and the score, and appeared to spark the team.
Ryan brought all three quarterbacks into a meeting Wednesday morning and told them of his decision. He said he consulted with several people, including his staff, and "put a lot of thought" into it before making up his mind late Tuesday night.
"It's really a decision I feel great about," he said.
It was perhaps the biggest call in Ryan's nearly four years as coach of the Jets, considering the sensitivity of the situation and the possible ramifications. He acknowledged that there were differing opinions among those he spoke to, but said he received no pressure from owner Woody Johnson and added that he was "absolutely" OK with the decision.
"I'm fortunate," he said. "I have a great relationship with my owner, with Woody. ... From the day Mr. Johnson hired me, he said it's 100 percent my decision who plays."
Sanchez, whose confidence was shaken with Sunday's miserable performance, gets a chance to bounce back from the first benching of his NFL career and regain the trust of his teammates. He has struggled the last several weeks, with two touchdowns and five interceptions in his last four games.
"He has to play better and he has to protect the ball better," Ryan said. "As a football team, we have to protect the ball better than we have."
He'll likely be on a short leash against Jacksonville - with McElroy possibly ready to go - but Ryan acknowledged that it might not be a quick hook if he struggles.
"If he throws one interception, it doesn't mean he's going to get benched, necessarily," Ryan said.
It's still uncertain if Tebow will be active against his hometown Jaguars after sustaining two broken ribs. He was medically cleared by team doctors to play, but Ryan chose to keep him active but not play against New England on Thanksgiving night and then made him inactive against Arizona.
If Ryan went with McElroy, a seventh-round pick in 2011 out of Alabama, it would have been a clear message that the franchise is moving on from Sanchez.
"I'll just keep working, go study this film and keep trying to improve," Sanchez said Sunday after the game. "I need to understand where the mistakes came from, keep studying, keep preparing, be ready to play next week and see what happens."
However, money might have played a role, too, with Sanchez owed $8.25 million next year in guarantees. But Ryan adamantly denied that factored into the decision.
"Absolutely zero," he said without hesitating.
Still, the Jets are likely stuck with Sanchez and his contract, so they need to see if he can rebound after the lowest point of his career.
"I believe in Mark," Ryan said. "He has the skill set that is pretty impressive."
If Sanchez can't bounce back, it will be an intriguing offseason for New York, especially since Tebow has not played much since being acquired from Denver in March and might not be back next year.
It didn't appear that Tebow was much of a factor in Ryan's decision. Ryan said all three quarterbacks would be in the mix, but didn't speculate as to whether he would have pulled Sanchez in favor of Tebow last Sunday if he were active.
Tebow was expected to have a major role in the offense, but instead has been just a spare part averaging about seven offensive snaps per game. He has been listed as the No. 2 quarterback on the depth chart, but if the Jets turned to McElroy, it would have meant that the No. 3 guy leapfrogged Tebow to start for the Jets.
Although Ryan said earlier in the week that it wouldn't play a part in his decision, the fact the team is playing on the road for the next two games should also help Sanchez.
He was booed mercilessly by the MetLife Stadium crowd last Sunday, particularly after each interception, and chants for McElroy were heard throughout the game. McElroy was cheered as he warmed up late in the third quarter, and there was growing sentiment among some fans and media that he earned a start after lifting the team.
"This is my opinion," Ryan said, "and I believe that sometimes you don't need to sit a guy for `X' amount of games."
The Jets are hoping he also sparked Sanchez, whom they deemed the face of the franchise just a few years ago when they traded up in the draft in 2009 and took him with the fifth overall pick. He helped lead New York to consecutive trips to the AFC championship game for the first time in team history, but it has been a bumpy ride since. Sanchez has been criticized the last two seasons for failing to take the next step in his development, and Ryan has been knocked for sticking with the quarterback for too long.
The two have been joined at the hip, and stand side-by-side during the national anthem before every game. Ryan was seen in the locker room consoling Sanchez after the game, his arm on his shoulder as the two spoke for a few minutes. Until last Sunday, the threat of being benched - even with Tebow on the roster - didn't appear to be a real possibility.
Now, Ryan has sent the message to Sanchez: Perform or else. And, Sanchez gets one more shot to save his job this season - and his status as the Jets' franchise quarterback.
"I think Mark is plenty tough," Ryan said. "I don't think there's any doubt he has the mental toughness."