While Sean Lewis isn’t technically the CU Buffs’ first million-dollar football assistant coach, Deion Sanders’ offensive coordinator is already knocking on the door. Based on documentation provided by CU Boulder to The Post on Thursday, Lewis, who was hired by Sanders away from a head-coaching gig at Kent State, agreed to join the Buffs on a three-year, $2.7-million contract. The 37-year-old play-caller is slated to make an $850,000 base and supplemental salary in 2023, a $900,000 salary in 2024 and a $950,000 salary in 2025. Coach Prime’s defensive coordinator, former Alabama assistant Charles Kelly, received the same deal as Lewis — three years at $2.7 million — with identical incremental pay increases. As coordinators, Lewis and Kelly received three-year contracts, while eight other assistants are working under two-year deals. Of those, tight ends coach and former Broncos assistant Tim Brewster; running backs coach Gary Harrell; linebackers coach Andre Hart; and cornerbacks coach Kevin Mathis are the highest-paid, with each slated to make $400,000 in salary for 2023 and $425,000 in 2024. Sanders’ salary pool of $5 million for his assistants also includes compensation for defensive ends coach Nick Williams ($350,000 in ’23; $375,000 in ’24), defensive tackles coach Sal Suneri ($325,000 in ’23; $385,000 in ’24), wide receivers coach Brett Bartolone ($315,000 in ’23; $340,000 in ’24) and offensive line coach Bill O’Boyle ($300,000 in ’23; $350,000 in ’24). A CU spokesman told The Post that should Lewis or Kelly leave the Buffs before their contracts end for an NFL or NCAA position, they would owe the university 25% of the salary for the current contract year as liquidated damages.