As Saturday opens, most of the focus is on players who will be cut as teams move from their 90-man roster limit as allowed in the preseason down to the 53-man roster limit permitted in the regular season. Cuts are not the only way to lower your roster number, however, and Saturday morning, there appears to be a major trade about to happen.

According to NFL Network’s Ian Rapoport and ESPN’s Adam Schefter, the Raiders are prepared to send three-time Pro Bowl and two-time First-Team All-Pro defensive end Khalil Mack to the Chicago Bears. Chicago is believed to be negotiating with Mack’s representatives on a new contract to solidify the trade.

Oakland was believed to be asking for at least two first-round picks and a player in return for Mack. It has not been disclosed as to what compensation they will actually receive.

UPDATE: Rapoport on NFL Network has said the Bears are sending two first-round picks to the Raiders. He said there is more included in the trade, but it was not yet clear if that includes a player or other draft picks.

Mack sat out the entire preseason, rather than play on his fifth-year option from his rookie contract. It did appear Mack was willing to continue to hold out into the regular season, leading to the Raiders to agree to trade him.

The Bears will likely move Mack to outside linebacker, using him as a pass rusher from there in a 3-4 base defense.

For more on the trade from the Oakland Raiders point of view, check out Silver and Black Pride. The Chicago Bears side of the trade can be found at Windy City Gridiron.