The banged-up New York Mets got much-needed reinforcements on Monday, activating three key players from the injured list, including Kevin Pillar, who is returning just two weeks after being hit in the face by a 94 mph fastball.

Besides Pillar, the Mets activated first baseman Pete Alonso and right-handed setup man Seth Lugo. The Mets also recalled outfielder Mason Williams, who was hitting .373 at Triple-A Syracuse. Pillar was not in the starting lineup for the Mets' game against the Arizona Diamondbacks at Chase Field on Monday night. Alonso is scheduled to hit third, while Williams is starting in center field and batting eighth.

Pillar had been out since being hit in the face by a pitch from Braves reliever Jacob Webb on May 17 that left him bloodied with multiple nasal fractures that required surgery.

Alonso, who leads the Mets with six home runs and 19 RBIs, was placed on the IL on May 21 with a sprained right hand, while Lugo has been sidelined since undergoing elbow surgery in the offseason.

The Mets have been besieged by injuries this season, with the number reaching as high as 17 players on the IL at one point. Despite the injuries, the Mets (25-20 entering Monday's games) are in first place in the National League East thanks to the contributions of several bench players thrust into the starting lineup.

Pillar was one of those bench players making major contributions while filling in for injured center fielder Brandon Nimmo. Other Mets starting position players still on the injured list include right fielder Michael Conforto, second baseman Jeff McNeil and third baseman J.D. Davis.

In corresponding moves Monday, the Mets optioned reliever Sean Reid-Foley, catcher Patrick Mazeika and outfielder Khalil Lee to Triple-A and designated outfielder Cameron Maybin and right-hander Sam McWilliams for assignment.