Late Tuesday night, the Chiefs and the Vikings had reached an agreement on a trade package, and at roughly the same time, Allen reached an agreement in principle on a contract with the Vikings. Upon reaching the contract agreement, Allen headed to the airport and left for Minnesota.
The Chiefs get Minnesota's first-round pick, No. 17 overall, and both of the Vikings' third-round selections. The teams also swapped sixth-rounders in the deal.
Allen, who had an NFL-best 15½ sacks last season despite being suspended the first two games, agreed to terms on a six-year deal that includes $31 million in guaranteed money. It could be worth more than $74 million if he reaches certain incentives. The contract will make Allen the highest-paid defensive player in the league.
It's a hefty price for the Vikings, who were 8-8 last year. However, defensive end was their top priority after losing Kenechi Udeze to leukemia and with first-round pick Erasmus James coming off a third knee surgery. Allen will team with Pro Bowlers Kevin Williams and Pat Williams to form one of the league's most formidable defensive lines.
Just 26 and in his prime, the 6-foot-6, 270-pound Allen was a supplemental fourth-round pick by the Chiefs out of Idaho State in 2004. He quickly established himself as a top-flight pass-rusher, but also has a tendency to over-pursue and sometimes gets out of position on running plays.
Allen was recognized as the premier defensive player in NCAA Division I-AA as a senior, but fell to the fourth round because of character concerns. Last year the commissioner suspended him the first two games because of multiple DUI convictions and if he is cited again, he could be suspended for an entire year.
The Chiefs, coming off a 4-12 season and undergoing a massive rebuilding campaign, have their own fifth overall selection, six of the first 82 picks and 13 altogether in this weekend's draft.
Knowing they were going to embark on a youth movement under coach Herm Edwards, the Chiefs began hoarding extra selections last year. They were worried, however, that their supplemental picks were only in the later rounds.
John Clayton is a senior NFL writer for ESPN.com. Information from The Associated Press was used in this report.