After starting his fourth season with the Winterhawks in 1994–95, Wiemer turned professional after 16 games and made his NHL debut with Tampa Bay. After playing in four seasons with the Lightning and struggling with the weight of offensive expectations due to his junior career, Weimer was traded at the deadline in the 1997–98 season to the Calgary Flames for Sandy McCarthy, a third round pick (Brad Richards) and a fifth round pick in the 1998 NHL Entry Draft on March 24, 1998.