MLB's digital-only national broadcasts continue this week with today's Nationals-Pirates contest at PNC Park, which will stream live in the United States exclusively on Facebook.
This National League clash is one of 25 streaming broadcasts scheduled for 2018 as part of MLB's partnership with the social media network.
Fans can catch the 12:35 p.m. ET contest at www.facebook.com/MLBLiveGames or by logging onto Facebook's MLB live page from their phones, tablets, smart TVs or other streaming devices. MLB Network will produce the game, with play-by-play man Rich Waltz, analysts F.P. Santangelo and Sean Casey and in-game reporter Stephen Nelson.
Both organizations will be represented in the booth. Santangelo began his seven-year Major League career with four seasons in Montreal, playing for the Expos several years before their move to D.C. to become the Nationals. Casey, a three-time All-Star, played 59 games for the Pirates in 2006, and also spent eight years in their division with the Reds.
How to watch on mobile and desktop
1. Search for "MLB Live" on Facebook
2. Follow the "MLB Live" show page
1. Download the Facebook video app on your TV or streaming device and search for "MLB Live"
2. Or stream the game from your phone to a TV on the same WiFi network by tapping the TV icon.
Upcoming Facebook games (all times ET)
• Wednesday, July 25: SF-SEA, 4:10 p.m.

What to know about the Nationals-Pirates game
This week's series in Pittsburgh features four newly minted All-Stars -- Nationals outfielder Bryce Harper, ace Max Scherzer and closer Sean Doolittle and Pirates closer Felipe Vazquez. They could soon be joined by a fifth as Washington shortstop Trea Turner is a candidate for the Camping World MLB All-Star Final Vote.
The Nationals bounced back from a five-game losing skid to take three of four games against the Marlins over the weekend. With stars like Harper and Daniel Murphy slumping at the plate, they received contributions from an unlikely source in National League Player of the Week Mark Reynolds, who hit a walk-off, pinch-hit homer on Friday and went 5-for-5 with a pair of home runs and a franchise-record-tying 10 RBIs on Saturday. 
The Pirates, meanwhile, are in the midst of a crucial stretch that could determine if they will be major sellers at the July 31 non-waiver Trade Deadline. A hot start had Pittsburgh looking to contend sooner than expected, but it's since fallen behind in the NL Central and Wild Card race.
"You don't want to overemphasize what a week can mean, but this is one of those weeks where 4-4 doesn't do us much good," general manager Neal Huntington said. "We need to make up some ground here in a short period of time. We need to show that we can continue to do that. Otherwise, we get to the point in time where we start to take a realistic look at this club."
Southpaw Giovany Gonzalez will start for the Nationals, looking to build upon a solid start against Miami after a string of inconsistent outings. He's 4-1 with a 4.20 ERA in eight starts against the Bucs since 2012.
Pittsburgh will counter with right-hander Trevor Williams, who's coming off the shortest start of his career. He was tagged for five earned runs in 2 1/3 innings vs. the Phillies on Friday. Williams faced the Nats on May 3 and allowed three runs and two homers in 5 2/3 innings.