Never drafted by an NHL team, Dykstra signed with the Buffalo Sabres organization on December 10, 1982. The rugged defenseman quickly earned a reputation as a tough, crease-clearing rearguard who had shown good overall improvement in his three years in the Sabres farm system, mostly with the Rochester Americans.
The Sabres had been looking for a bone-crunching defenseman for some time, and by 1985-86 Dykstra had improved to the point where he was ready to play in the NHL. And play he did. He appeared in 64 games with Buffalo, scoring 4 goals and 21 assists while collecting 108 PIM. He quietly impressed in a small defensive role, providing some depth and physicality to the Sabres weak blueline.
Dykstra had some trouble in 1986-87. He ran into injuries as well as the sophomore jinx. He appeared in 37 games with the Sabres but collected no goals and just 1 assist. He also added 179 PIM as his role had changed to more of an enforcer role. The Sabres blueline had been improved by the additions of savvy veteran Lee Fogolin and skilled Tom Kurvers, so Dykstra's ice time was reduced significantly..
By the end of the 1987-88 season Dykstra was right out of the Sabres plans. Not given enough ice time to progress as a player, Dykstra scored 1 goal and 1 assist in 27 games before being traded to his hometown Edmonton Oilers. Dykstra finished the year on a mini scoring spree - collecting 2 goals and 5 points in 15 games with the Oilers. However Dykstra, acquired for his size and willingness to drop the gloves, was never used in the playoffs.
The Oilers failed to protect the punishing defenseman prior to the start of the 1988-89 season, but the Pittsburgh Penguins quickly nabbed him. He played in a career high 65 contests, collecting 1 goal and 6 assists along with 126 PIM.
Dykstra signed with Hartford as a free agent in the summer of 1989 but only played in 9 games for the Whalers. Instead he spent most of the season back in the minor leagues, a place he would get used to over the coming years. He never would appear in the NHL again following his stint in Hartford, and instead bounced around the AHL, IHL, ECHL and CHL until he retired in 1996.
At the NHL Dykstra was strictly a one dimensional player who had to play within his limitations to be quietly effective. He was big and strong and was best when throwing his weight around, especially in front of his own net. However he lacked NHL skating agility, thus limiting the effectiveness of his hitting game.