Manager Dave Roberts had said earlier Friday that the plan was to activate Van Slyke by Sunday, with Puig to the DL as a possibility, but the team instead announced the move just minutes before the start of Friday night's 4-2 win over the Braves.
"It was one of those where it was just a forthright conversation, trying to figure out where he was at," Roberts said. "We're trying to play both sides, keep him available, but at some point we just had to make a decision on getting him healthy.
"He's not the player that he can be if he's not healthy, especially with his legs, so we made that decision."
Van Slyke had finished an eight-game rehab assignment with Class A Advanced Rancho Cucamonga and Triple-A Oklahoma City and had already rejoined the team. He went 0-for-1 as a pinch-hitter on Friday.
Howie Kendrick was out of the starting lineup Friday for the second straight game since hurting his shoulder playing first base Wednesday, but Roberts said the veteran was feeling better and should be back in the lineup Saturday.
"He says the discomfort has dissipated since yesterday," Roberts said. "It didn't come out of the socket or anything like that. I just felt, for today, it's prudent to give him that extra day, and I'll get him back in there tomorrow."
Jack Baer is a reporter for MLB.com based in Los Angeles. This story was not subject to the approval of Major League Baseball or its clubs.