Even when they had an entrenched starter like Brett Favre or Aaron Rodgers, the Packers believed in the importance of drafting quarterbacks anyway to develop as backups or chips to trade in the future.
Cook said he was surprised to end up on a team with a young starter like Carr, thinking he might end up in Dallas as the heir apparent to Tony Romo. But McKenzie moved ahead of the Cowboys for the 100th pick by trading picks in the fourth (No. 114) and fifth (No. 154) rounds to the Cleveland Browns.
"I'm glad I found a home," Cook said. "A little bit of a wait. I'm glad the whole process is over."
The Raiders have now selected a quarterback in three of the past four drafts.
Before the start of the fourth round, multiple teams had shown interest in trading up for the first pick of the round, sources told ESPN's Adam Schefter.
The Browns owned the first two picks in the fourth round. They used the first to take Wisconsin outside linebacker Joe Schobert and then sent the second to the Raiders. The 114th overall pick was used to take wide receiver Ricardo Louis.
Cook had been projected by many to go higher in the draft to a team looking for a potential starting quarterback but ended up being the seventh quarterback selected, going behind less-heralded players like NC State's Jacoby Brissett and USC's Cody Kessler.
"Anytime you see another quarterback drafted in front of you it hurts," Cook said. "I'm a competitor. Obviously I think I'm one of the best quarterbacks in this draft class. But things are never easy. Nothing is ever perfect. Everything I was able to accomplish at Michigan State was never easy. Going on to the NFL, it's definitely going to get a little bit harder and more difficult."
Cook had a prolific college career, leading Michigan State to a 34-5 record and two Big Ten championships in three years as starter for the Spartans. He threw for 71 touchdown passes and 9,194 yards in his career but completed just 57.5 percent of his passes, and some scouts questioned his accuracy.
He also faced criticisms of his leadership skills after teammates decided not to elect him as team captain.
"I don't think you can win that many games and be that successful at a program without being a leader," Cook said. "I think all that stuff was so far from the truth. Everything will work itself out. People want to talk and say all that stuff, but they've never even sat down to talk to me or get to know me as a person."
Cook will compete with former undrafted free agent Matt McGloin to be Carr's backup in Oakland. McGloin is eligible to be a free agent next year, and the Raiders wanted to add another quarterback to the mix.
ESPN Stats & Information and The Associated Press contributed to this report.