If Boston signs Meszaros after the start of the draft, the Flyers said, they will receive an additional fourth-round pick in 2015.
Meszaros, 28, coming off an injury-plagued season in which he played just 11 games, had five goals, 17 points, and a plus-1 rating in 38 games this season. He became expendable when the Flyers acquired Andrew MacDonald from the Islanders on Tuesday.
Holmgren thanked Meszaros for his four years with the Flyers.
"Andrej's been through good times and bad times in this organization," Holmgren said. "He was a good guy, and he did have a tough 18 months with all the injuries he dealt with, and he never once complained - even this year, when he wasn't in the lineup. He was a good soldier about it."
Like MacDonald, Meszaros can become an unrestricted free agent after the season.
In the 2010-11 season, Meszaros' first with the Flyers, he was named the winner of the Barry Ashbee Trophy as the team's best defenseman. He had eight goals, 32 points, and a plus-30 rating that season.
Meszaros had back surgery in 2012 and season-ending shoulder surgery last year, but he has played solidly this season.
Breakaways. Holmgren said he never made an offer for Vancouver center Ryan Kesler, as some media outlets reported. . . . Erik Gustafsson becomes the Flyers' No. 7 defenseman.