Caldwell ended weeks of speculation Friday by hiring defensive coordinator Larry Coyer and special teams coordinator Ray Rychleski. Caldwell also promoted receivers coach Clyde Christensen to assistant head coach.
Coyer spent the past two seasons as an assistant with Tampa Bay after spending seven seasons with the Denver Broncos, including the final four as defensive coordinator. Rychleski has been a college coach throughout his career, spending last season at South Carolina.
"Larry and Ray have been successful in every stage of their careers, and their talents and input will show in our on-field performance," Caldwell said in a statement
The hiring of Coyer and Rychleski, who worked with Caldwell in the college ranks, had been expected. The promotion of Christensen was not a surprise, either, since all three have long ties to Caldwell.
Coyer and Caldwell spent time together at Iowa, while Rychleski and Caldwell worked on the same staff at Penn State and Wake Forest. And Christensen served on former coach Tony Dungy's staff the past 13 seasons, the last eight alongside Caldwell.
"Larry and Ray will be valuable additions in key areas for the club," Caldwell said. "Both have a wealth and wide range of experience that will benefit our players."
Dungy resigned Jan. 12 after seven seasons leading the Colts, and the changes mark the start of a new era for the franchise. One day after being introduced as Dungy's successor, Caldwell decided not to renew the contract of special teams coach Russ Purnell. A week later, defensive coordinator Ron Meeks resigned. He accepted the same job with the Carolina Panthers.
Under Purnell, the Colts typically ranked in the bottom half of the league in opponents' starting field position, while Meeks changed the image of a defense once considered among the NFL's worst into one of the league's most opportunistic.
But Meeks' tenure was marred by inconsistency.
Caldwell hopes the new coaches provide more stability.
Coyer's 44-year coaching tenure includes four seasons at Iowa, three of those when Caldwell played for the Hawkeyes and one in which Caldwell served as a graduate assistant.
Coyer spent the past two seasons as Tampa Bay's assistant head coach and overseeing the defensive line.
Rychleski's extensive resume spans nearly three decades, mostly in the college ranks. He worked with Caldwell in 1991 at Penn State, then followed Caldwell to Wake Forest in 1993 when Caldwell took over as head coach. Rychleski remained on Caldwell's staff through 2000.
While working with Dungy in Tampa Bay, Christensen coached quarterbacks, tight ends and served as offensive coordinator.
"Many people know the contributions Clyde has made to the organization during the past seven years. He has helped the Colts function as one of the NFL's top offenses," Caldwell said. "His coaching manner and personal style exemplify the attention to detail and demand for performance we require at all times. I welcome his expanded role with our staff."
The Associated Press contributed to this report.