When new Saints head coach Sean Payton said he wanted a roster defined by smart football players, former microbiology major Jon Stinchcomb had to sense his moment had arrived.

Stinchcomb, a 2003 second-round draft pick out of Georgia who still plans to attend medical school, has his best chance to crack the starting lineup at right tackle — if he can stay healthy.

“I definitely didn’t think my first real opportunity would come my fourth season. I don’t think anybody expects that, especially when you’re drafted pretty early,” Stinchcomb said after a recent training camp practice. “That’s in the past. I’ve grown from it and I’m excited about this season.”

Drafted during the regime of coach Jim Haslett, Stinchcomb, whose older brother, Matt, was an NFL offensive lineman for seven years, accepted playing sparingly as he learned the position through his first two seasons.

He anticipated playing more in his third year. However, the Saints drafted Jammal Brown and put him at right tackle at the opening of training camp in 2005. Then Stinchcomb ruptured his right patellar tendon, putting him out for the season.

As he spent the ensuing months in Georgia recovering from surgery, it wasn’t clear what kind of future he’d have in New Orleans, especially after Haslett was fired and replaced by Sean Payton.

To Stinchcomb’s surprise, the Saints traded veteran tackle Wayne Gandy to Atlanta and moved Brown over to the left side, opening the right tackle position.

“This is by far the best opportunity I’ve had since being a Saint. … I definitely didn’t predict the Wayne Gandy trade,” Stinchcomb said. “Mentally, I’m in a good place knowing that this year I’ve got a great opportunity to get out there and help this team.”

Coaches call the 6-foot-5, 315-pound lineman sharp, and he probably should be, given that he’s been often been surrounded by teachers. His grandmother was a principal, while his mother, stepmother and two aunts are teachers, as is his wife, who had been with Desire Street Academy before Katrina and now is with Jesuit High School.

Stinchcomb has said he’s the kind of guy who enjoys New Orleans more for its historic architecture, art museums and fine food than the night life on Bourbon Street — yet another reason why coaches might like him.

“Jon’s a very smart football player. He’s very aware of what’s going on and that’s an advantage,” offensive line coach Doug Marrone said. “The more the player knows what to do, then obviously that becomes a reaction and we can concentrate on his technique.”

Payton also is complimentary of Stinchcomb’s grasp of the play book, but worries about his health.

After the second practice of training camp last Saturday morning, Stinchcomb’s right knee began to swell. He spent the next three-and-a-half days of practice pedaling a stationary bike before getting back on the field Wednesday.

Stinchcomb couldn’t help but wonder whether his string of setbacks was about to continue.

“A lot of thoughts cross through your mind, but I always had to feel like it was temporary,” he said. “Structurally, it was all right.”

Marrone said Stinchcomb has good upper-body strength. But even Stinchcomb acknowledges he lacks experience, having been on the field for fewer than two dozen offensive snaps.

Marrone said the key for Stinchcomb will be whether the soon-to-be 27-year-old lineman can use his strength and intelligence to strike hard into defensive linemen and drive them back with consistency, and to stand his ground on pass protection.

“He has a lot of strength, we just have to get that to carry over onto the field,” Marrone said.

And while Stinchcomb has another profession to pursue in medicine, he would gladly delay that as long as possible, especially after seeing how his brother’s career was cut short by complications stemming from recent back surgery. Matt Stinchcomb had blood clots pass into his lungs and had a pulmonary embolism, his brother said.

“That really made it clear to me how quickly your career can change. It was a shock to him. He goes in to have an operation to further his career and it ends up cutting it short,” the younger Stinchcomb said. His medical career is “not something that has ever gone to the wayside, but I love playing the game of football, so that can wait.”