SAN JOSE, Calif. -- Before Sean McDermott was one of the NFL's best young defensive coordinators mentioned as a possible head-coaching candidate, he was a walk-on at William & Mary, a Division I-AA program in Williamsburg, Va. By his senior season, McDermott was team captain, an all-conference safety and a member of the Atlantic 10 all-academic team.

Seventeen years later, he's the man responsible the Panthers' dominant defense, which ranks second in the league behind only the Broncos, according to Football Outsiders' metrics. A lot of what McDermott experienced at William & Mary has shaped him into the coach he is today.

"Those were obviously great experiences," he told this week. "I knew I wanted to coach at an early age. My father was a college and high school coach and I just love being around the game. That's kind of how I was as a player, and I ended up coaching the spring of my fifth year when coach [Jimmye] Laycock approached me and asked if I wanted to give it a try. And I'm grateful for it -- that was my start.

"I think it's no accident that a number of coaches and personnel guys have come out of William and Mary. To me, it's a credit to the type of program coach Laycock runs. There are set rules, there is clarity when it comes to expectations. You're expected to go to class and be a student-athlete. There are no cutting corners."

McDermott was a true freshman in 1993 and played on the same team with current Steelers coach Mike Tomlin. Tomlin, a 6-foot-2 wide receiver, finished his William & Mary career with 101 receptions for 2,046 yards and a school-best 20 touchdowns. His 20.2 yards-per-catch average in 1994 was also a school record.

We asked McDermott about Tomlin's game.

"He wasn't a fast wide receiver, but he was a long strider. I'd compare him to Devin Funchess -- he has that length and was willing to go over the middle to make the great catches," he said. "But what I remember the most about Mike was that he was a leader."

But perhaps the best player on those teams was quarterback Shawn Knight, a 5-foot-10, 175-pound dynamo who could do everything. In 1993, he completed 125 of 177 passes (70.6 percent) for 2,055 yards, 22 touchdowns and four interceptions. In fact, if Knight was a few inches taller he almost certainly would have been a high-round pick.

"No question," McDermott said. "I told my wife the other night -- she's a Delaware grad -- that I remember a play against Delaware where it was a quarterback sneak in a short-yard situation. Shawn jumped over the pile, got pushed back and never really got tackled. He came off the pile, spun off around the corner and disappeared around the end for a 30- or 40-yard gain just because he was an incredible athlete."

Sean McDermott's defense is one of the NFL's best. (USATSI)
Sean McDermott's defense is one of the NFL's best. (USATSI)

Back in 2014, Laycock told the Virginian-Pilot, "I can remember many times at practice with Shawn that the ball would never touch the ground. He was always so accurate -- as accurate as any quarterback I've ever seen in practice, and then that obviously carries over into games."

As a junior, Knight also began playing baseball and a year later, he was drafted in the 13th round by the San Diego Padres. He had a brief stint in the CFL, but the NFL never came calling. In retrospect, that wasn't because Knight wasn't ready for the NFL, but that the NFL wasn't ready for Knight.

"I would say he's like Russell Wilson," said McDermott, comparing Knight to one of the league's most athletic quarterbacks. "Smaller guy, nimble, got that cannon for an arm, fast. Shawn was special. ... Back in the day, I was really honestly in awe of Shawn not only because of his athleticism, but because of who he was and the way he handled things on and off the field. He was a true professional."

It's the culmination of those relationships and experiences that have led McDermott to this point, one game away from a Super Bowl title.

"To me, when you look back at our team, and I think about the great teams I've been on, they all had that special chemistry that's built up through high-character individuals that just love being around one another," he said. "And I would say the same thing about this football team here in front of us."