Beauchemin, 35, spent nine of his 13 NHL seasons with Anaheim, standing second among franchise leaders in scoring by a defenseman with 179 points (53 goals) and a plus-47 rating.
He earned $3.5 million last season and left the Ducks' exit interviews in early June, talking as if he expected to rejoin Hampus Lindholm as the Ducks' top defensive pair.
Yet Ducks General Manager Bob Murray said after trading for veteran defenseman Kevin Bieksa, 34, on Tuesday that Beauchemin and his agent told Murray on Tuesday morning that they believed a three-year offer was available in free agency.
Murray, considering his salary cap situation and the fact that Beauchemin has required surgery on both knees, said he "couldn't do that."
TVA Sports in Canada reported Wednesday that Beauchemin will earn $4.5 million annually in his deal with Colorado, also receiving a no-movement clause.