St. Croix spent most of the next 5 seasons in the minor leagues with various teams. He really found a home in Maine of the AHL where he established himself as a number one goalie. By 1980 he led the entire AHL in GAA with a 2.90 mark, good enough to earn him (and partner Robbie Moore) the Hap Holmes Award for fewest goals against in the entire league!
In those 5 long years in the minors, St. Croix was called up for 10 games of NHL action in total, sporting a 3-5-2 record. But after his spectacular 1980 season in Maine the Flyers elevated St. Croix to the big club, becoming the full time backup to Pete Peeters in 80-81. He recorded a career best 2.49 GAA and his only 2 NHL shutouts in 27 games. He also played admirably in the 1981 playoffs when Peeters went down with an injury. St. Croix battled hard with a 4-5 record and 1 shutout in 9 post season contest.
After showing good promise, St. Croix was given a better shot In 1981-82. However things didn't go as well for Rick. He played in 29 games in 81-82 but his GAA rose to 3.89.
His struggles continued in 1982-83 when he played only 16 games with Philadelphia. The Flyers felt they needed stronger goaltending in their backup position, so they traded Rick to Toronto in exchange for veteran goalie Michel "Bunny" Larocque. The move was also made to give hot shot rookie Pelle Lindbergh a mentoring figure.
St. Croix played 16 more games with Toronto that season, recording a 3.80 GAA. Obviously the team in front of Rick was pretty weak, but as often happens with goalies, St. Croix took more than his fair share of the blame for the poor results.
His playing time in Toronto decreased over the next two years while his GAA ballooned well over 5.00. He was demoted to the minor leagues. He finished his career in 1985-86 with a strong showing with the IHL's Fort Wayne Komets, sharing the Norris Trophy (fewest goals against) with Pokey Reddick.
In his retirement St. Croix operate his own goaltending schools