Hall of Famer Steve Young was in Nashville, Tenn., on Dec. 17, the night Mark Sanchez's career turned into a country-music song -- a sad ballad about hitting rock bottom after a long fall.

"To me," Young said this week, "it just looked like a capitulation from a quarterback."

That's a fancy way of saying Sanchez gave up.

Marty Mornhinweg (shown working with Geno Smith) faces a Hail Mary in saving Mark Sanchez's career. AP Photo/Bill Kostroun

Young, working the New York Jets-Tennessee Titans game for ESPN, saw what America saw that Monday night. Sanchez threw four interceptions, lost a fumble with the game on the line and lost his starting job, which he may never get back.

"Capitulation" is a harsh word -- also hard to rhyme in a song -- but there's no doubt Sanchez was throwing to ghosts on that ill-fated night in Dixie.

Now here we are, six months later, and Sanchez is trying to win back his team and its fans. The man charged with fixing him is a blast from Young's past, offensive coordinator Marty Mornhinweg, who faces perhaps the biggest challenge of his career.

Mornhinweg, 51, is a long way from Young's San Francisco 49ers, Brett Favre's Green Bay Packers and Donovan McNabb's Philadelphia Eagles, previous stops in his career as an assistant coach. In Sanchez, he inherits a quarterback who needs to be rebooted.

"Marty can get everything Mark has," said Young, who played under Mornhinweg in the late 1990s. "Mark has to decide what that really is. Part of me thinks he has plenty in the tank but has just lost his desire to get it done. He's broken down. Unfortunately, that's what I see. But if there's something to get, Marty will get it."

Mornhinweg has to be a teacher, a technician and a psychologist -- and even that might not be enough to get it done. But at least he brings a quarterback's perspective into the classroom and on the practice field, which wasn't the case with his predecessor, Tony Sparano, an old offensive line coach who had no experience with quarterbacks.

"He's like one of those professors in college that you like going to their class, and that was rare," Sanchez said of Mornhinweg, who learned his football from two of the brightest minds in the sport's history.

Mornhinweg was coached in high school by Mike Holmgren and mentored early in his NFL coaching career by the late Bill Walsh. He was a camp quarterback for the 49ers in 1986, when Walsh was the coach, and returned a decade later as the coordinator.

By then, Walsh had left the sideline for the front office. He became Mr. Miyagi to Mornhinweg's Karate Kid. They talked. Often.

"When he was up in training camp, shoot, I tried to grab him every day for a few minutes," Mornhinweg said. "He loved talking football as well. Looking back on it, it might have been good for both of us, certainly for me."

Walsh died in 2007, but his wisdom still resonates with Mornhinweg, who applies his mentor's methods to the daily tasks of his job -- such as installing a new play. Walsh was known as a terrific teacher, able to explain and simplify complex schemes. Mornhinweg prides himself on the same.

If you believe in the transitive property, you might say Walsh is teaching Sanchez, with Mornhinweg serving as the conduit.

When Mornhinweg was hired in January, he brought a white legal pad into the film room and broke down every Sanchez play from the past three seasons. He graded him in four major categories: instincts, decision-making, accuracy and timing. He also evaluated his arm, athleticism and leadership.

What did he see?

Mornhinweg said he saw a quarterback, in 2010, who orchestrated six fourth-quarter comeback victories. Impressive stuff. He also saw a quarterback who committed a league-high 52 turnovers in 2011 and 2012. Ugly stuff.