The Colorado Avalanche forward will serve the remainder of his suspension during Games 5 and 6 of the Stanley Cup Second Round against the Vegas Golden Knights. Kadri would be eligible to play in Game 7, if necessary.
Colorado would be eliminated with a loss in Game 6 at Vegas on Thursday.
Kadri appealed to Shyam Das. the independent arbitrator, as was his right under the NHL/NHLPA Collective Bargaining Agreement, after NHL Commissioner Gary Bettman denied his original appeal May 31.
The suspension was handed down May 21 for an illegal check to the head of St. Louis Blues defenseman Justin Faulk in Game 2 of the first round at Colorado on May 19.
Kadri has served seven games: Games 3 and 4 against the Blues and five games against the Golden Knights.
He had one assist in two postseason games before being suspended, and has scored 29 points (12 goals, 17 assists) in 36 Stanley Cup Playoff games. He scored 32 points (11 goals, 21 assists) in 56 regular-season games this season.
"The eight games, I'm a little surprised to be honest with you," Avalanche coach Jared Bednar said when the suspension was announced. "I looked through all the headshot suspensions for the last year. A lot of two-gamers get handed out that were significant hits to the head. We've had some guys put out with hits to the head that you know are still out with no suspension and two games.
"So I thought, generally the rule of thumb, in playoffs you get a little less, and he got significantly more, so it is what it is. We have to deal with it and we need other guys to step up, and I'm not going to worry about it past today. We have to live with the decisions [NHL Player Safety] make and they make them for a reason. We don't always have to agree when it's their decision and you've got to live with it."
The incident occurred with 13:34 remaining in the third period. Kadri was given a match penalty. Faulk, who did not return in Game 2, did not play the final two games of the best-of-7 series.
Kadri had been suspended two times previously during the postseason.
When playing for the Toronto Maple Leafs, he was suspended three games for boarding Boston Bruins forward Tommy Wingels in Game 1 of the 2018 Eastern Conference First Round. He also was suspended for the remainder of the 2019 first round for cross-checking Boston forward Jake DeBrusk in Game 2; the Bruins won the series in seven games.