The Kansas City Chiefs won their final 10 games of the regular season and reached the postseason at 11-5 largely because their defense finished third in the league in points allowed per game.
The Chiefs picked Peters with the 18th overall selection in the draft out of Washington, and he rewarded them with eight interceptions, two of which he returned for touchdowns, and a forced fumble. His eight interceptions were tied with Reggie Nelson for the most in the league and a primary reason why the Chiefs were second in the NFL with 22 total interceptions this year.
In fact, the 23-year-old tallied a pick on his first NFL play in Week 1 against the Houston Texans, and he notched a pick-six against the Denver Broncos' Peyton Manning in Week 2. Peters was also the Week 15 AFC Defensive Player of the Week in a victory over the Baltimore Ravens in which he picked off two passes and ran one back 90 yards for a crucial late touchdown.
Peters also earned a Pro Bowl nod this year, won the NFL Defensive Rookie of the Month in December with four interceptions in his last five games and was named second-team All-Pro by the Associated Press.
Nathan Jahnke of Pro Football Focus said Peters “led all cornerbacks in positively graded coverage plays,” which is all the more impressive considering he often found himself guarding the opponent’s best receiver throughout the season as a rookie. Pro Football Focus highlighted just how often quarterbacks tested the Washington product in 2015:
Pro Football Focus @PFF
Marcus Peters was targeted 137 times during the regular season. More than any other corner in PFF history.2016-1-4 13:15:04
Adam Teicher of ESPN.com detailed the impact Peters made on his team in his first campaign: “The addition of Peters has made the Chiefs a different kind of team. Last year, they were begging for turnovers and had just six interceptions. This year, forcing turnovers is a weekly part of their game and Peters leads the parade.”
Even head coach Andy Reid was ready to dispense plenty of praise for the playmaker, per Teicher:
Cocky is not the word. Confident, I'd tell you is the word. Competitive is probably a better word. He never thinks he's out of a play. He's going to challenge people around him. He's not afraid to do that.
I think if you talk to the other guys, they'll tell you that. They trust him out there. Is he going to give up a play here or there? ... Yes. But the players have confidence in him and they know he's going to bring it every snap.
That willingness to bring it every snap earned Peters recognition as the best defensive rookie in the league this season.