The team cut its longest-tenured player Sunday night. The sides weren't talking Monday, but the Rams remained optimistic about an agreement that would bring Bruce back for a 13th season.
Coach Scott Linehan termed the release a "temporary setback." He blamed the lack of a collective bargaining agreement for the move.
"This CBA deal has kind of put things a little bit out of whack," Linehan said. "I feel very positive about resuming talks and getting that uniform back on our guy.
"We'll do whatever we can to make that happen."
Bruce, 33, had a salary cap figure of $10 million for next season. He was due a $1.5 million roster bonus Monday, the first day of the free agency period, as part of an $8.1 million salary. But the opening of free agency has been delayed for three more days.
Bruce was entering the final year of a seven-year, $42 million contract he signed in 2000.
The Rams reportedly offered a three-year deal worth about $9 million, including a $5 million contract in the first season.
"Isaac has been an integral and valuable member of our organization for a long time, both on and off the field," said Jay Zygmunt, the team's president of football operations. "This has been a difficult process.
"However, we remain optimistic that a contract extension can be completed in the near future."
Bruce has been with the team since 1994, the year before it moved to the Midwest from Los Angeles, and has been to four Pro Bowls. He considered holding a news conference but decided against it.
Bruce is the Rams' career leader in receptions (813), yards receiving (12,278) and touchdowns receiving (77). He also caught the game-winning touchdown pass in the Rams' lone Super Bowl victory after the 1999 season.
His yards receiving rank 12th in NFL history.
Last season, Bruce missed five games with turf toe and had 36 receptions for 525 yards. In 2004, his last full season, he had 89 catches for 1,292 yards with six touchdowns.
Over his career, he's been durable. Bruce has played every game in seven seasons and late last season he felt pretty much like the player the Rams drafted in the second round in 1994.
Linehan said it was much to soon to worry about life without Bruce.
"Obviously, we've got to have a contingency plan, but I'm going to look at it from the standpoint that we're going to get it done," Linehan said. "We'll address that if we have to.
"We're talking about a guy that, to me, you don't replace."