In April 2008, Butler decided to leave the University of Denver early to sign with the NHL Buffalo Sabres. Butler, who likely would have been captain of his college team next season, is the fourth player — and third junior — in the past three years to leave DU early to sign an NHL deal. Named to the All-America second team on April 11, 2008, Butler was recognized as the Pioneers' best defenceman and two-way player. He had 17 points (three goals) this season, and had a team-high 110 blocked shots and a plus-10 rating.
Butler joins Matt Carle (Tampa Bay Lightning), Ryan Dingle (Anaheim Ducks) and Geoff Paukovich (Edmonton Oilers) in leaving DU after their junior season. Two years ago, Paul Stastny signed with the Avalanche after his sophomore season.
| Regular season | ||||||||
|---|---|---|---|---|---|---|---|---|
| Season | Team | League | GP | G | A | Pts | PIM | |
| 2003–04 | Sioux City Musketeers | USHL | 55 | 3 | 6 | 9 | 37 | |
| 2004–05 | Sioux City Musketeers | USHL | 60 | 6 | 22 | 28 | 90 | |
| 2005–06 | Denver Pioneers | NCAA | 32 | 7 | 14 | 21 | 26 | |
| 2006–07 | Denver Pioneers | NCAA | 37 | 10 | 17 | 27 | 40 | |
| 2007–08 | Denver Pioneers | NCAA | 36 | 3 | 14 | 17 | 30 | |