Rasmussen's strengths are in one-on-one situations, relying on his quick reactions and vision for the game, but he has been criticized for not commanding his field on especially corner kicks and free kicks, due to his lack of height.
Club career
Born in Stenvad near Grenaa, Steffen Rasmussen played his youth football in minor club Stenvad Boldklub, before joining the youth setup of AGF Aarhus. He spent a year with lower-league Jutland Series club Grenaa IF, before returning to AGF. He established himself as second-choice keeper behind Erik Boye, and signed a professional contract with AGF in March 2002. Under new manager Poul Hansen, Rasmussen made his Danish Superliga debut for AGF against Odense Boldklub on 10 November 2002, replacing Boye at half-time. As Boye suffered a back injury, Rasmussen played the next three games in a row. Boye returned to the starting line-up, but following another injury, Rasmussen established himself as AGF's first choice, playing the last 13 games of the Danish Superliga 2002-03 season. In August 2003, AGF brought in Rune Pedersen to replace the retiring Boye. Rasmussen began the Danish Superliga 2003-04 season as starting goalkeeper, but lost his place to Pedersen in April 2004 following a slump in form. He was second choice for the Danish Superliga 2004-05 season, but following an injury to Pedersen in April 2005, Rasmussen got another chance and again established himself in the starting line-up. He was the undisputed first-choice goalkeeper for the Danish Superliga 2005-06 season, missing only four games through a hand injury. He was named the AGF player of the season, but could not keep AGF from being relegated. He stayed with AGF in the Danish 1st Division. He suffered a shoulder injury during the season, but helped the club bounce right back into the Superliga. He played all 33 games of the Danish Superliga 2007-08 season. Before the Danish Superliga 2008-09 season, he was named captain of the team by AGF coach Ove Pedersen, replacing Peter Graulund. He missed only two games that season, due to a hand injury. In the 0–1 defeat to FC Midtjylland on 14 April 2010, Rasmussen got his first red card in his AGF career, following a foul on Jonas Borring. He missed two games through suspension. Despite playing 31 of 33 games, Rasmussen could not keep AGF from being relegated at the end of the Danish Superliga 2009-10 season.