He made his professional regular season debut and first career start in the Carolina Panthers’ season-opener against the New Orleans Saints and recorded five combined tackles during their 23–20 loss. Davis struggled during their loss against the Saints and was demoted to backup strong safety behind Marlon McCree for the following game. On September 18, 2005, Davis recorded two solo tackles and made his first career sack in a 27–17 victory against the New England Patriots in Week 2. Davis sacked Patriots’ quarterback Tom Brady for a ten-yard loss during the second quarter. On December 4, 2005, Davis played as an outside linebacker against the Atlanta Falcons and was used as a quarterback spy to contain Falcons’ quarterback Michael Vick. Davis was instrumental in the Panthers’ 24–6 victory against Atlanta, making four combined tackles and being credited with half a sack. Davis and strong safety Mike Minter lined up in the box and were used to contain Vick as the Panthers defeated the Falcons for the first time in franchise history since the latter had drafted Vick in 2001. In Week 17, Davis collected a season-high five solo tackles during a 44–41 victory at the Falcons. He finished his rookie season in 2005 with 38 combined tackles (31 solo) and 1.5 sacks in 16 games and one start.