Infielder Stephen Drew returned from the disabled list, with Grace once again optioned to Syracuse, and the Nationals began a nine-game swing through California on May 29. On the first game of the road trip, the Nationals obtained their second shutout win of the year, beating the San Francisco Giants 3–0 behind a strong start by Tanner Roark. The game was marred, however, by an eighth-inning brawl that broke out after Giants reliever Hunter Strickland, facing Harper for the first time since the Nationals right fielder went 2-for-2 with two home runs off him during the 2014 National League Division Series, drilled Harper in the hip with a 98 mph fastball with his first pitch. Harper tossed aside his bat and charged Strickland on the mound, throwing his helmet wide to the left of Strickland before the two players traded punches. They were separated by their teammates, with Giants first baseman and former National Michael Morse quickly getting between them before being bowled over (and concussed) by Giants pitcher and former University of Notre Dame football star Jeff Samardzija, and ejected from the game. Harper said after the game that he decided immediately that the pitch was intentional: "You never want to get suspended or anything like that, but sometimes you've got to go and get him. You can't hesitate. You either go to first base or you go after him, and I decided to go after him." He suggested Strickland was retaliating for the 2014 home runs (which Strickland denied), saying, "It was three years ago. ... I don't know why he's thinking about it. He's got a World Series ring, it's on his finger, and he can look at it every single night he wants to." Both Harper and Strickland were issued suspensions by Major League Baseball, with Harper receiving a four-game penalty, which was lowered on appeal to three games. He began serving the suspension on May 31.