He entered training camp competing with veterans Jerame Tuman and Matt Kranchick for the starting tight end position. Miller was named the starting tight end to begin the regular season. He made his professional regular season debut in the Pittsburgh Steelers' season-opener against the Tennessee Titans and caught his first career touchdown on a three-yard pass from Ben Roethlisberger in a 34–7 victory. On October 23, 2005, Miller caught a season-high six passes for 58 receiving yards and a touchdown during a 27–13 victory over the Cincinnati Bengals. The next game, he made three receptions for 18-yards and a season-high two touchdowns in a 20-19 win against the Baltimore Ravens. During a Week 17 matchup with the Detroit Lions, he caught three passes for a season-high 62 receiving yards in a 35-21 victory.