Propp repeated his playoff heroics in the 1989 playoffs until he was concussed by an illegal hit by Montreal Canadiens defenseman Chris Chelios in the first game of the Wales Conference Finals. The play precipitated the infamous incident late in Game 6 -- with the series already sewn up for Montreal -- in which Flyers goaltender Ron Hextall made a beeline out of his net to attack Chelios.
A decade of excellence came to an end on March 1, 1990. A little less than two months after the Flyers traded former captain Dave Poulin to Boston, the club dealt to Boston another player who was key to their success in the 1980s: Philly traded Propp to the Bruins for a 1990 second-round pick (a pick used on the selection of defenseman Terran Sandwith).
By that point of the 1989-90 season, the Flyers knew they weren't making the playoffs. Clarke thought the 31-year-old Propp - who had been limited to 40 games and slumped to 13 goals and 28 points - was nearing the end of the line in his career. Additionally, the player's contract was set to expire at the end of the year and Propp wanted a new multi-year deal.
In Clarke's words in Full Spectrum, "It was the right time for Brian [to go]. And I was glad it was to Boston. He was a good player for this organization for a long time, and I thought sending him to a good team might salvage his career."
Clarke's generosity in sending Propp to a contender was appreciated by the player but the player's production was hard to replace and his departure contributed to the Flyers' decline that led to a five-year spell of missing the playoffs. Only the previous season, Propp had led the Flyers in scoring. At the time of the trade to Boston, he was not finished as a productive NHL player.
Upon his arrival in Boston, Propp posted 12 points in the final 14 games and then added 13 points in 20 playoff games as the Bruins reached the Final. The next season, he joined the Minnesota North Stars and returned to the Final again, compiling 73 points in 79 regular season games and 23 points in 23 playoff tilts.
Terran Sandwith, the player whom the Flyers chose with the 2nd round pick sent over by Boston, spent two-plus seasons with the team's AHL affiliate in Hershey without earning a callup to the big club (in a period where the club had a revolving door of defensemen and tried just about anyone in the system with a pulse). He later appeared in 8 NHL games with Edmonton before returning to the minors and making several stops in Europe.
After the 1989-90 season, the Flyers let Clarke go as the GM. He was soon hired by Minnesota, where Propp was among his players on the club that made a surprise trip to the Final in 1991.
Propp played through the 1993-94 season in the NHL and also made stops in the Swiss National League with HC Lugano - where he played on a line with the legendary Igor Larionov - and even a stint playing in France.
Following his retirement, Propp made his permanent home in south Jersey. He has undertaken a host of different business ventures. Despite suffering a stroke in 2015, he made a remarkable recovery. Propp maintained an extremely busy schedule of public appearances and is active in a variety of civic organizations and remained deeply involved with the Flyers Alumni Association and a regular player for the Flyers Alumni Team.
Among previous ventures in his professional and public life, Propp spent a lengthy stint as the Flyers radio broadcast analyst (1999-2000 to 2007-08 seasons), hosted his own Flyers-centered cable television show and even ran for political office in New Jersey. Brian and wife Kris, who met on a Flyers cruise in the summer of 1987 and were married in 1992, decided to make their home in Cinnaminson, NJ, with children Jackson and Paige.
In addition to being a member of the Flyers Hall of Fame, Propp is also a member of the Saskatchewan Hockey Hall of Fame. In Nov. 2014, he added induction into the Philadelphia Sports Hall of Fame to his post-career honors, becoming the eighth individual Flyers player honored.
Other Flyers selections include Clarke, Barber, Bernie Parent, Howe, Hextall, Eric Lindros, John LeClair and the late Rick MacLeish. Additionally, Broad Street Bullies era coach Fred Shero earned posthumous honors and the 1973-74 Stanley Cup winning team received a collective induction. The late Hobey Baker is also honored in the Philadelphia Sports Hall's hockey category.