Kragthorpe hit a home-run with the addition of former Michigan defensive coordinator Ron English. English replaces Mike Cassity as Louisville's defensive coordinator.
"I'm extremely excited that Ron English will be joining our football staff in the position of defensive coordinator," said Kragthorpe. "Ron brings an intense passion for the game of football and his enthusiasm is contagious. He did a tremendous job at the University of Michigan and was instrumental in their success."
English, 39, spent five seasons as an assistant at Michigan - three as a secondary coach; two as defensive coordinator. English, who played at California, also served as an assistant at Arizona State, San Diego State and Northern Arizona.
In 2006, his first season as Michigan's defensive coordinator, the Wolverines defense ranked as one of the best nationally, finishing No. 1 against the run, fourth in sacks, seven in third down defense, 10th in total defense and 15th in scoring defense.
This season, despite losing several key performers to the National Football League, Michigan ranked No. 8 nationally against the pass, 22nd in scoring defense and 24th in total defense.
English is also considered one of the nation's top recruiters. His presence on the recruiting trail could pay major dividends right away for Louisville.
"Ted is a tremendous football coach who brings a great level of experience to our staff," said Kragthorpe. "He was a great linebacker as a player and has excelled as a linebacker coach, a defensive coordinator and head coach."
Prior to his stint at Duke, where he compiled a 6-45 record in four seasons (2004-07), Roof served as a linebackers coach and defensive coordinator at Georgia Tech (1999-2001).
As Georgia Tech's defensive coordinator in 1999, Roof's defense ranked 12th nationally against the run and 20th nationally in scoring defense. Roof's 2001 defense ranked 32nd nationally in total defense.
A former All-ACC linebacker at Georgia Tech, where he ranks seventh on the all-time career tackles list, Roof was nominated for the Broyles Award, given annually to the nation's top assistant coach.
The Cardinals were also looking for a wide receivers coach to fill the void left by the departure of former offensive coordinator/wide receivers coach Charlie Stubbs. Kragthorpe will pull double duty next season and coach the wide receivers.
Louisville is also expected to name a replacement for former Strength and Conditioning coach Jason Veltkamp, who resigned his position to join former Louisville coach Bobby Petrino at Arkansas. That announcement could come as soon as Friday.