An MRI confirmed that New England Patriots wide receiver A.J. Brown suffered a high ankle sprain in Wednesday’s season-opening loss to the Seattle Seahawks that is expected to sideline him for at least four weeks, a source told NFL Network’s Ian Rapoport on Thursday.

The Patriots were bracing for not having Brown, who quickly emerged as quarterback Drake Maye’s go-to target in the receiver’s debut for the team. Earlier Thursday, coach Mike Vrabel said Brown’s right ankle injury “is the one we will have to monitor” because it could impact his availability.

The Patriots can expect to be without Brown for the Sept. 20 home opener against the Pittsburgh Steelers, then road games against the Jacksonville Jaguars (Sept. 27) and Buffalo Bills (Oct. 4). New England then has back-to-back home games against the Las Vegas Raiders (Oct. 11) and New York Jets (Oct. 18).

X-rays did not reveal a fracture.

“I know he’ll do everything that he can to get back as quickly as possible,” Vrabel said before the results of the MRI were known.

Veteran Mack Hollins took over the majority of Brown’s role Wednesday after he left the game early in the third quarter. The Patriots will also need more from former Green Bay Packer Romeo Doubs, who had a costly drop and finished without a catch in his Patriots debut after signing a four-year, $68 million free agent contract in the offseason.

Four-year veteran Pop Douglas (slot) and second-year players Kyle Williams and Efton Chism III are also on the depth chart. Receiver was one of the team’s deepest positions in training camp, leading to the trade of former starter Kayshon Boutte to the Houston Texans.

Brown remained down after a third-down incompletion in which Maye was throwing in his direction with Seahawks cornerback Nehemiah Pritchett in tight coverage. Pritchett’s right knee appeared to land on Brown’s ankle with the force of his body weight. Brown grabbed for the back of his right leg as he sat up.

He slowly walked to the sideline, going to the medical tent for an extended period. He then walked to the locker room with members of the athletic training and medical staff.

The Patriots traded a 2028 first-round pick and 2027 fifth-round pick to acquire Brown from the Philadelphia Eagles on June 1.

Earlier in the game, Brown helped set up the Patriots’ first touchdown by coming back for an underthrown deep ball by Maye and drawing a defensive pass interference penalty. Maye hit rookie tight end Eli Raridon for a 2-yard touchdown on the next play.