But the reality of starting the regular season minus Mack hammered home with general manager Reggie McKenzie, as the hours to the league deadline of establishing the initial 53-man roster crept closer.
"My whole thought process was to get Khalil [signed]," McKenzie said Saturday, via NBC Sports Bay Area. "It was at the end, in the final hour, that it just hit. It hit hard and heavy. It was not a plan to trade him at all."
The Raiders adjusted by shipping Mack to the Chicago Bears in a stunning trade, and the Bears promptly made Mack the highest-paid defensive player in the league with a six-year, $141 million contract extension.
The transaction was quickly scrutinized around the league, as it involved one of the NFL's elite defenders and it isn't common for a team to part ways with a generational player.
Oakland's decision to move Mack, however, ultimately came down to the inability between the team and Mack's representation to reach an agreement on the bottom line.
"We will pay top dollar," McKenzie said, via NBC Sports Bay Area. "We couldn't get around giving Khalil what he wanted. We will pay top dollar to top players.
"We just could not get it worked out with Khalil. When it seemed like it was going that way, we decided to make a move with the trade. We will be able attract players. ... We'll find a way to continue to play good football. We're not worried about the outside perception of free agency. We will get free agents in here when it's time to do that and we will keep our own. Sometimes you can't keep them all. That's just the way it goes."
In the meantime, the Raiders shift their focus to the regular season following Saturday's developments.
While the team wants to put the trade behind them, McKenzie understands there will be locker room angst because Mack was a popular player among teammates.
"It's going to sting with them," McKenzie said. "Players protect themselves and their teammates. That's how it should be. They're going to miss Khalil. I'm going to miss Khalil. We all will miss Khalil. Let's make that point known now. We all will miss him, but we will all move on."