Last night the Cubs staved off elimination, winning their second game of the World Series. It had something in common with their other win in Game 2: they faced Trevor Bauer, and they didn't face Andrew Miller. Cleveland did pitch Cody Allen, but only after the Cubs had taken the lead, and left in Aroldis Chapman for a career-high eight outs to counter him.
Exciting as last night was for Cubs fans, it's worth keeping that in mind, because the trio of Allen, Miller, and Kluber has been freakishly effective in the playoffs, especially when it counts. By Win Probability Added, those three pitchers, in that order, rank first through third throughout this year's playoffs.
WPA is a cumulative statistic that measures how much a player's actions increase or decrease his team's chances of winning. Here's how Fangraphs describes an example:
For example, say the Rays have a 45% chance of winning before Ben Zobrist comes to the plate. During his at-bat, Zobrist hits a home run, pushing the Rays’ win expectancy jumps to 75%. That difference in win expectancy (in decimal form, +.30) from the beginning of the play to the end is Ben Zobrist’s WPA for that play. The pitcher receives a -0.30. If Zobrist strikes out during his next at bat and lowers his team’s win expectancy by 5%, his overall WPA for the game so far would be +.30 – .05 = +.25, as WPA is a cumulative statistic and is additive.
The highest-WPA event of the 2016 playoffs, for instance, came when Conor Gillaspie tripled off Aroldis Chapman in the eighth inning of Game 3 of the NLDS. Before Gillaspie got his hit, the Giants had a 36.6 percent chance of winning the game; after Gillaspie gave them the lead, it increased to 91.9, a swing of 55.1 percentage points, or .513 in win probability added.
To have three players on the same team rank 1-2-3 in WPA for the playoffs is uncommon. The last time it happened was 2007, with Jonathan Papelbon, Josh Beckett, and Manny Ramirez for the 2007 Red Sox; the only other time it's happened in the past 20 years was for the 1996 Yankees, who were also the last team for all three to have a WPA over one.
WPA, being cumulative, tends to go to players who play a lot and play well. Andrew Miller has thrown 17 innings this postseason, the most of any reliever, giving up one run. Corey Kluber has thrown 30.1 innings, second behind Lester, and has given up three runs (Lester's given up eight). Cody Allen has outperformed Aroldis Chapman: Allen's pitched 11.2 innings over nine games with zero earned runs and 22 strikeouts, while Chapman's pitched 13 innings over 11 games with three earned runs, 18 strikeouts, four saves, and two blown saves.
And in this series, Allen, Miller, and Kluber combined for three wins and a save. If the Cubs are going to win the World Series, they'll almost certainly have to get through all three of them.