FOXBOROUGH, Mass. -- New England Patriots rookie receiver Malcolm Mitchell is expected to miss about four weeks after initial tests showed he suffered a dislocated left elbow during Thursday night's preseason game against the New Orleans Saints, a source told ESPN.

X-rays on Mitchell's elbow were negative, but he's expected to also have an MRI.

Mitchell was hurt late in the second quarter, when he was being dragged down after making an 8-yard reception along the right sideline. He sprung to his feet and immediately walked to the locker room with a member of the Patriots' medical staff, holding his left arm close to his body.

A fourth-round draft choice out of Georgia, Mitchell didn't enter the game until the fifth series. In 15 snaps, he totaled four catches for 55 yards, developing a quick rapport with quarterback Jimmy Garoppolo, who was 11-of-18 for 168 yards.

Pats rookie Malcolm Mitchell, who had four catches for 55 yards, injured his left elbow in the second quarter of Thursday's preseason opener. Jim Rogash/Getty Images

Mitchell, whose work as a public advocate for children's reading has earned headlines, has been separating from his competition in practice and has positioned himself to potentially be a big part of the Patriots' offensive plans alongside receivers Julian Edelman, Danny Amendola and Chris Hogan atop the depth chart.

At Georgia, Mitchell, who is 6-foot-1, 200 pounds, played in 47 games (35 starts) and finished third in school history with 174 receptions for 2,351 yards and 16 touchdowns. In 2014, he was named Georgia's Comeback Player of the Year after missing almost all of the 2013 season because of a knee injury.

For the Saints, linebacker Stephone Anthony, a 2015 first-round pick, left on a cart before halftime because of an unknown injury. Coach Sean Payton declined to comment on Anthony's injury after the game, a 34-22 Patriots win.

ESPN's Mike Reiss, Mike Triplett and Adam Caplan contributed to this report.