Julius Peppers was slapped with the franchise player tag by Carolina on Thursday, making it more difficult for the star defensive end to get his wish and leave the Panthers.

The tag was applied after the Panthers agreed on a new contract with left tackle Jordan Gross. That cleared the way for Carolina to use the team’s only franchise tag on Peppers, who had 14 1/2 sacks last season but expressed his desire to leave the Panthers and their 4-3 scheme for a team that plays a 3-4 defense.

The move came on the final day for teams to apply a franchise designation, which keeps a player under the control of his current team for an average salary of the top five players at his position. Overall, 14 of the NFL’s 32 teams protected players with the franchise tag.

In addition to Peppers, among those tagged on Thursday were cornerback Dunta Robinson of Houston; tight end Bo Scaife of Tennessee; linebacker Leroy Hill of Seattle; and offensive tackle Max Starks of Pittsburgh.

Meanwhile, All-Pro cornerback Nnamdi Asomugha re-signed with Oakland, avoiding the franchise tag he had last season by agreeing to a three-year contract that’s thought to be the richest ever given to a defensive back. It’s value is estimated at $30 million.

But the most intriguing move involves Peppers, the second overall pick in the 2002 draft. His big season followed a 2007 in which he had just 2 1/2 sacks.

A person close to Peppers said on Wednesday that the defensive end would agree to be traded to only four teams, including the Dallas Cowboys, who do not have a first-round pick and would be unlikely to make a deal — a team that signs a franchise player owes his original team two first-rounders, although deals have been made for less than that.

That could leave the Panthers facing the prospect of a holdout or eating up a huge portion of the salary cap by spending more than 10 percent on one player.