The Oakland Raiders sent shockwaves through the entire NFL on Saturday morning, when they made the decision to trade former Defensive Player of the Year Khalil Mack to the Chicago Bears. As the afternoon has progressed, the Raiders have made yet another trade - this time for quarterback depth behind Derek Carr.

According to a report by NFL Network's Ian Rapoport, the Raiders have traded with the Buffalo Bills for quarterback AJ McCarron. According to ESPN's Adam Schefter, the Raiders have given the Bills a fifth round pick in exchange for the veteran backup.

In a corresponding move, the Raiders parted ways with backup Connor Cook. Schefter reported shortly after McCarron's trade that the team had released Cook.

McCarron, a former national championship-winning quarterback with the Alabama Crimson Tide, had been competing for the Buffalo Bills' starting quarterback job with rookie Josh Allen and second year player Nathan Peterman.

After being drafted by the Cincinnati Bengals in the fifth round of the 2014 NFL Draft, McCarron spent the first four years of his NFL career as the backup to Andy Dalton, and had the Bengals on their way to their first playoff victory since 1990 before the team completely melted down in the 2015 AFC Wild Card Game against the Pittsburgh Steelers. McCarron got an opportunity to compete for the starting job with the Bills, but ended up becoming an afterthought in Orchard Park after the Bills drafted Allen with the seventh-overall pick in the Draft.

Meanwhile, Cook had been drafted in the fourth round of the 2016 Draft by the Raiders after falling down the draft board despite a storied career at Michigan State. Playing in only one game during his Raiders career, Cook had not appeared to be poised to serve as a capable backup for Derek Carr. In his only NFL appearance during the regular season, a Week 17 game against the Denver Broncos after both Carr and then-backup Matt McGloin were injured, Cook completed 14 of 21 passes for 150 yards with a touchdown, an interception, and one lost fumble.

With the Raiders in the playoffs, Cook became the very first quarterback in the Super Bowl era to make his NFL debut in a playoff game. Facing the Houston Texans on the road in the AFC Wild Card Round, Cook fell flat on his face. Looking totally outmatched against the Texans' defense, Cook completed only 18 of 45 passes for 161 yards, one touchdown, and a miserable three interceptions - that one touchdown coming in garbage time as the Raiders went one and done.

With McCarron, Jon Gruden will hope that his Raiders now have a good insurance policy should anything happen to Derek Carr, as was the case at the end of the 2016 season.