Haggan practiced all summer at the "mike" position but was moved outside after Dumervil tore a pectoral muscle early in training camp that will sideline him at least until December.
"They released me this morning. The coaches couldn't really give me an explanation," Ayodele told FOX31 in Denver. "To tell you the truth I was really caught off guard. They said I did everything right, but that they just wanted to go a different route."
Ayodele, who signed with Denver after spending the past two seasons with the Miami Dolphins, made eight tackles in the Broncos' two preseason games this season, including six against the Lions on Saturday.
"That is the last thing I would expect because I started the last two preseason games. This is the first time this has happened to me like this, but I have to stay encouraged the same way I have encouraged other guys over the years," Ayodele told FOX31.
Ayodele said the Broncos told him they released him this early so he had a chance to sign with another team.
Ayodele is one of three starting linebackers in the NFL who has played in every game since 2002. He played for Miami (2008-2009), Dallas (2006-07) and Jacksonville (2002-05) after being drafted by the Jaguars out of Purdue.
Last year, Ayodele started 15 games for the Dolphins and tallied 70 tackles, 60 of them solo, to go along with a forced fumble and two fumble recoveries. He has started at least 11 games in each of his eight seasons.
Information from The Associated Press was used in this report.