Herm Edwards analyzes his former team's recent decisions and where the relationship between the Chiefs and John Dorsey could have fallen apart. (1:18)

KANSAS CITY, Mo. -- The Chiefs extended the contract of coach Andy Reid on Thursday but will be looking for a new general manager after parting ways with John Dorsey.

Reid's extension is for five years, a source tells ESPN. The signing was expected. The move with Dorsey -- who arrived in Kansas City as general manager in 2013, a few weeks after Reid -- was surprising.

Chiefs chairman and CEO Clark Hunt said he made the decision not to extend Dorsey's contract beyond the 2017 season, which led to Thursday's development.

"After consideration, we felt it was in his best interests and the best interests of the team to part ways now," Hunt said in a statement. "This decision, while a difficult one, allows John to pursue other opportunities as we continue our preparations for the upcoming season and the seasons to come.''

Although the Chiefs described Dorsey's exit as a mutual decision, a source told ESPN's Adam Schefter that the general manager was fired.

The Chiefs made no mention of a search for Dorsey's replacement, but a source told ESPN's Field Yates that the search will begin immediately. The source said the Chiefs will consider both internal and external candidates for the position.

"I want to thank Clark, the Hunt family and the Chiefs fans for the opportunity to be a part of Chiefs Kingdom over the last four seasons," Dorsey, 56, said in the statement. "I believe this team is well positioned for the future and I wish Coach Reid, the players and the entire organization all the best."

Andy Reid's tenure with the Chiefs will continue past this season but general manager John Dorsey's time with the team ended Thursday. David Eulitt/Getty Images

Reid, 59, has a 43-21 regular-season record with the Chiefs, who, at 12-4, won the AFC West title last season. They reached the playoffs in three of the past four seasons and won a playoff game for the first time in 22 years in January 2016, when they beat the Houston Texans.

"My family and I have been very pleased by the success the franchise has sustained over the last four seasons under Coach Reid," Hunt said in the statement announcing the extension. "He has already established himself as one of the best coaches in the league and he is well on his way to solidifying a place among the all-time greats. We are proud to have him leading our football team, and I look forward to working with him to bring a championship to Chiefs Kingdom.''

Before Reid and Dorsey arrived in Kansas City, the Chiefs had four seasons of four wins or less in a six-year span.

"I'd like to thank Clark and the entire Hunt family for the opportunity to continue my coaching career here in Kansas City," Reid said in the statement. "We've made quite a bit of progress over the last four seasons, but we are not done yet. We are going to continue to work towards our ultimate goal of winning championships. I've been blessed by the support of the community, our fans, the Hunt family and the entire Chiefs staff. I'm looking forward to the years ahead as the head coach of the Kansas City Chiefs."

Reid, who was hired by the Chiefs after 14 seasons with the Philadelphia Eagles, has a regular-season record of 173-114-1 in 18 seasons as a head coach. He is 11-12 in the playoffs (1-3 with the Chiefs). Among active coaches, only New England Patriots coach Bill Belichick (260) has won more games.