what exactly happened to him after thr 95-96 season
Injuries pretty much. He started and finished the 1996-97 season pretty strong but injuries in between hurt his progress - 17 games missed due to sprained MCL and 3 to 5 missed due to a hand injury - throughout the year.
The worse and career changing injury however would come at the start of the 1997-98 where Eric Lindros cross-checked Nieds in the back of the head during the season's game-opener which led to a concussion and resulted in 10 straight games being missed. He comes back but after playing 10 games, he dislocates his right thumb which results in 17 more games missed. He returns to fight Lindros but the damage to Niedermayer has already been done and his style/game begins to change...he lost his confidence...he lost his edge and started sporting a visor at some point that season (which he still wears now). After his fight with Lindros, he plays in 13 games but then has to sit out 8 games due to post concussion syndrome. He tries one more time and plays in 9 games but develops "flu" like symptoms (post concussion syndrome) and sits out the remaining 13 games of the season.
He was jumped and suckerpunched by Andrei Nazarov (Tampa Bay) during preseason for the 1998-99 season which gave him headaches and resulted in Nied's remaining physical play (finishing his checks and hitting) to become nonexistant. Sad but true...he ended up becoming a responsible two way checking forward instead of the skilled powerforward he was hyped up to be. Laters.