Another year, another Wild Card game, and I'm going with the Pirates to win again. But it's close.
Let's begin with the pitching matchup, in which Madison Bumgarner will face Edinson Volquez. Bumgarner is better for reasons too obvious to belabor, and the fact that he's a good lefty pitcher adds to his edge, although not by a ton. The Pirates have a respectable 97 wRC+ against lefties, which puts them just below the middle of the pack in the National League.
Among Pirates regulars, Travis Snider has led the way against lefties this season (1.054 OPS), although that's surely a fluke, since Snider isn't one of the Pirates' top hitters and is left-handed himself. Below him are a number of players who have also hit well against lefties: Andrew McCutchen (.912), Josh Harrison (.856), Jordy Mercer (.803), and Starling Marte (.781). Gaby Sanchez, who I'm sure will be in the lineup tomorrow, has a .746 OPS against lefties. No one who's outright bad against lefties is likely to be in the lineup -- the only two players who struggled against lefties in a significant sample size were Pedro Alvarez and Gregory Polanco.
Unlike that of the Reds last year, the Giants' lineup isn't unbalanced against either side of the plate. They're strong against righties, with Buster Posey (.844), Pablo Sandoval (.824) and Hunter Pence (.779) leading the way. Shortstop Brandon Crawford has done most of his damage so far this year against lefties, but he's a decent hitter and a lefty himself, so I don't see why he shouldn't be able to make noise against a righty.
The Giants will, however, have some significant holes in their lineup. Joe Panik, their likely starter at second base, hit just one home run this year. Injuries to Angel Pagan and Michael Morse could mean that the Giants will start our old friend Travis Ishikawa in left field. Ishikawa is a lefty, so he's a good fit offensively for tomorrow night, but he hasn't played much outfield before, and left field at PNC Park is big. Center fielder Gregor Blanco is no one to fear. And if the Giants opt to go with light-hitting Juan Perez somewhere in the outfield, all the better. So the Pirates do have better position players for tomorrow night, although that assumes that Russell Martin is healthy.
The Bucs will, unfortunately, give all of that small advantage back and then some with the starting pitching matchup. So let's turn to the bullpen. Assessing a team's relievers is tricky, in part because assessing the skill level of any reliever at a single point in time is difficult. One could make the argument that the most dominant relievers to suit up tomorrow will be John Holdzkom and Bucs castaway Hunter Strickland, and it would have been very tough to see either of those guys coming this time last year. Beyond Strickland, the Giants have enough decent arms (Sergio Romo, Santiago Casilla, and Jeremy Affeldt in particular, with the possibility that a starter like Yusmeiro Petit could come of the bullpen as well) that I don't see a clear advantage for the Pirates here. Also look for another former Pirates minor leaguer, Erik Cordier -- I doubt the Giants will roster him, but I would, since he throws a million miles an hour and could be terrifying in a short stint.
If this game were in San Francisco, I'd pick the Giants, even though they haven't played that well in the second half and even their fans seem to have already given up on them. Bumgarner is good, and I don't see the Pirates having enough of an edge elsewhere.
Until, of course, you add in that this game is at home. In a vacuum, the edge a team has at home is typically about eight percent, so the home team will win 54 percent of the time. That edge is probably slightly greater for the Pirates, who are well tailored for their home park -- think, again, of the big left field at PNC and the difference between Marte and Ishikawa out there. That's probably enough to give the Pirates a slight advantage. It's just one game, and these edges are tiny, but I'll take the Pirates. And yes, I know the score is exactly the same one I predicted last year. I undershot the Bucs' margin of victory against the Reds. Let's hope I do that again.
Prediction: Pirates 4, Giants 3