Sources told ESPN and NFL Network that the Bears are expected to trade for the All-Pro pass rusher. ESPN reported that the teams have an "agreement in place," while the teams are still working on the trade.
Sources told NFL Network that the Bears will send the Raiders at least two first-round picks in the swap.
Mack, 27, has been one of the best defensive players in the NFL since entering the league as the No. 5 pick overall in the 2014 NFL Draft. The 6-foot-3, 252-pound defender is a three-time Pro Bowl selection and a two-time All Pro. Mack had 78 total tackles, 10.5 sacks, three passes defensed, a forced fumble and a fumble recovery in 16 starts last season.
He has never missed a start during his four-year tenure, but never reported to the Bears this offseason as he wanted to negotiate a new contract. The Raiders exercised the fifth-year option on Mack's rookie contract last summer, giving him a $13.8 million salary in 2018.
Chicago is expected to negotiate a long term deal with Mack, which could pay him more than 2017 Defensive Player of the Year Aaron Donald. The Los Angeles Rams star just received a $135 million extension.