With the game tied at 3 and one out in the 11th, Neil Walker doubled against Wesley Wright, the eighth pitcher the Cubs used in the extended game. Gregory Polanco and pinch-hitter Brent Morel both walked to load the bases for Harrison, who lined a single to center and is now is 4-for-5 with the bases loaded this season. Pinch-hitter Tony Sanchez added a sacrifice fly for a 5-3 lead.
"He's a very good player," Cubs manager Rick Renteria said of Harrison. "He's a gifted baseball player. He does a lot of little things. Surprisingly, he shows you some speed, some pop, some tremendously acute aptitude for the game. He's flexible -- they can move him around. He's a kid who, from what I understand, is a very hard worker and very driven and doesn't take anything for granted."
However, Harrison moved to shortstop in the 11th and chased down a popup by the Cubs' Matt Szczur, but he sustained a leg injury and had to leave the game. He was being evaluated with left ankle discomfort and was not in the lineup for the regularly scheduled game.
The loss snapped the Cubs' home win streak at six, while the Pirates, who are battling for a playoff spot, ended a four-game losing streak.
"I thought the bullpen did a nice job in general," Renteria said. "We had a couple opportunities and weren't able to cash in on them. We just fell a little short."
Friday's game was interrupted twice by rain, which has been a recurring theme for the Cubs this season. They now have had 17 games delayed, totaling 24 hours and 38 minutes, and two games have been suspended.
When play was stopped, the two teams were tied at 3 with one out in the Pirates' seventh. Pittsburgh had tallied in the first when Harrison doubled and scored on an errant throw by third baseman Luis Valbuena.
In the second, Arismendy Alcantara singled and one out later, Valbuena doubled to left, with his ball bouncing into the ivy in left field for a ground-rule double. Alcantara scored on Jorge Soler's sacrifice fly, and one batter later, Valbuena tallied on a throwing error by Harrison to go ahead, 2-1.
Jose Tabata tied the game at 2 with an RBI double over Alcantara in center field in the fourth. Tabata then scored on Harrison's double.
Rain halted play for 37 minutes in the Pirates' fifth, and when it resumed, the Cubs tied the game in their half on Chris Valaika's two-out RBI single.