As a sophomore member of the 2004 Michigan Wolverines football team, Long competed with senior Dave Schoonover and juniors Mike Kolodzieg, Rueben Riley, and Mike Barishaj for the starting position vacated by the graduated Pape. Long impressed the coaches by playing through a turf toe injury. The battle came down to him and Kolodzieg. Long made his Michigan debut on September 4, 2004, in a 43–10 victory over Miami University. He made the travel squad, but he did not play against Notre Dame in the Michigan – Notre Dame rivalry game the following week at Notre Dame Stadium. Kolodzieg started the first two games, but Michigan averaged only 85.5 yards rushing, which ranked 94th nationally among 117 Division I teams. Long became a starter in the third game on September 18 against the San Diego State Aztecs football team. Over the course of the season, he started eight games and Kolodzieg started 4 at right offensive tackle. Kolodzieg also started one game at left tackle. A week after Long was moved into the starting lineup, David Baas was moved from left offensive guard—where he had been a 2003 second team All-American—to center so that Leo Henige, Jr. could enter the starting lineup. After the move, Baas was the co-Rimington Trophy winner that season. The team finished the season as the 2004 Big Ten Conference Co-Champions and were awarded the Big Ten Conference's Bowl Championship Series Bowl game bid. By the time Michigan was preparing for the 2005 Rose Bowl, the team was averaging 156.18 rushing yards per game, which ranked 56th in the nation. Long earned a second team All-Big Ten Conference recognition from the coaches, while linemates guard Matt Lentz, tackle Adam Stenavich and tight end Tim Massaquoi were first-team selections. Baas was Big Ten Offensive Lineman of the Year. Long also received honorable mention All-Big Ten recognition from the media. Long and teammates Chad Henne and Mike Hart were named to Rivals.com's 2004 Freshman All-America first team. Long had post-season shoulder surgery and missed 2005 spring practice. In fact, because of the large number of injured players, the team canceled the culminating spring practice intrasquad scrimmage game and instead held an open practice in which players participated in drills.