Most college teams have more than 99 players on their rosters, so they often have offensive and defensive players with the same number — since players with the same number cannot be on the field at the same time. At Alabama last season, that meant duplicates for Nos. 2, 3, 4, 5, 6 and 9. But at places as varied as Michigan, Notre Dame and Temple, the demand for low numbers has grown so much that some coaches have devised reward systems to determine who gets them.

“If you have a single-digit number,” Notre Dame wide receiver C. J. Sanders said, “it’s kind of a big deal.”

The new interest from defensive players aside, quarterbacks, running backs and wide receivers remain the biggest single-digit enthusiasts. The last four Heisman Trophy winners have worn single-digit uniform numbers, and the trend is expected to continue this year, as most of the leading contenders — Louisville quarterback Lamar Jackson (No. 8), Clemson quarterback Deshaun Watson (No. 4, which was unretired specifically for him), Washington quarterback Jake Browning (No. 3), Florida State running back Dalvin Cook (No. 4) and Peppers (No. 5) — fit the mold.

Yet the increased demand from recruits and current players has made for a tough balancing act for coaches. Several have chosen to follow the path taken by Virginia’s Mendenhall and Notre Dame’s Brian Kelly by effectively making the jerseys valued prizes and having their players compete to earn them.

Sanders, a Notre Dame sophomore, wore No. 9 last season, but there was no guarantee that he would keep it. For the first time in his seven years in South Bend, Kelly did not announce the single-digit roster numbers until this summer. He told a radio station that high school recruits had been pressing him about wearing single digits, so instead of promising them to anyone, he and his staff created a point system to track players on and off the field. Players who had the most points would be rewarded with single-digit jerseys. Sanders was one of the top performers, and he traded his No. 9 for No. 3, which he had worn in high school.

Kelly had an entirely different plan for the biggest prize, No. 1. He told his players that he would alternate it each week, giving it to the player who most deserved it. But the plan did not work out as he had hoped; after the Fighting Irish started the season 1-3, Kelly discontinued the practice. No Notre Dame player has worn the number in the team’s last three games.