27, 2001, the Buffalo Bills signed Clements to a five-year, $6.70 million contract that includes $3.17 million guaranteed. Throughout training camp, Clements competed to be a starting cornerback against Lance Brown, Ken Irvin, and Jimmy Williams. Head coach Gregg Williams named Clements the third cornerback on the depth chart to begin the regular season, behind Antoine Winfield and Ken Irvin. He was also named the starting kick returner to begin his rookie season. He made his professional regular season debut in the Buffalo Bills' season-opener against the New Orleans Saints and recorded one solo tackle in their 24–6 loss. On September 23, 2001, Clements made one tackle, deflected a pass, and returned his first career interception for a touchdown during their 42–26 loss at the Indianapolis Colts. He intercepted a pass by quarterback Peyton Manning and returned it for a 61-yard touchdown in the third quarter to mark the first score of his career. On October 18, 2001, Clements earned his first career start after he surpassed Ken Irvin on the depth chart. He recorded three solo tackles and broke up a pass in the Bills' 13–10 win at the Jacksonville Jaguars in Week 5. In Week 8, Clements collected three combined tackles, deflected a pass, and returned a punt for a 66-yard touchdown during the second quarter of a 30–24 loss to the Indianapolis Colts. In Week 14, he collected three combined tackles and made his first career sack on quarterback Tom Brady during a 12–9 loss at the New England Patriots. On December 23, 2001, Clements collected a season-high 11 solo tackles, a season-high three pass deflections, and intercepted a pass by Michael Vick in the Bills' 33–30 loss at the Atlanta Falcons in Week 15. He completed his rookie season in 2001 with 63 combined tackles (53 solo), ten pass deflections, three interceptions, three forced fumbles, a sack, and a touchdown in 16 games and 11 starts. He also had 30 kick returns for 628-yards and four punt returns for 81-yards and a touchdown. 2002 Defensive coordinator Jerry Gray chose to retain Clements and Antoine Winfield as the starting cornerbacks in 2002. On October 20, 2002, he recorded four solo tackles, four pass deflections, three interceptions, and a touchdown during a 20–13 victory at the Miami Dolphins in Week 7. He intercepted three passes by quarterback Ray Lucas and returned an interception by Lucas for a 29-yard