watford manager aidy boothroyd, who had been a coach at leeds during the previous season, was pleased with the signing, stating that carlisle was "exactly the type of defender i wanted". carlisle was placed straight into watford's starting line-up and played his first match for his new club on 6 august 2005, but he could not prevent the team losing 2–1 to preston north end at vicarage road. on 29 august 2005, carlisle scored his first goal for the club, claiming the winning header in a 2–1 victory over derby county at pride park. soon after, carlisle scored two goals in a competitive match for the first time in his career, grabbing both in watford's 2–1 win against wolverhampton wanderers in the second round of the league cup.