It’s fairly well-accepted that assigning wins and losses are a flawed metric. As we say earlier in the week, pitchers like Tarik Skubal can have an excellent game, but still get tagged with the L through no fault of their own, simply because the offense has a bad day. Worse, relief pitchers can vulture wins almost regardless of their performance, if they are fortunate enough to be the pitcher of record when their team takes the lead. Some of the rules make no real sense in modern baseball. Saying
a starting pitcher must go five innings to qualify for the win may have made sense in 1950, when the rule was formalized: 77% of starters did so. But last year, the figure was only 59%.
You need look no further than the recent World Baseball Classic final to see why the rules are unfair. Eduardo Rodriguez tossed 4.1 brilliant and scoreless innings for the Venezuelan team, restricting the USA line-up to just one hit. But he would not have been eligible for a win under any circumstances, because he did not complete the requisite five innings. Instead, the “win” went to reliever Andrés Machado. But his performance – two ER in 1.1 innings – was blatantly the worst of the six pitchers used by Venezuela that day. Indeed, Machado was the only one who allowed any runs at all.
Nearer to home, there have been some even more stark examples of misattributed wins and losses. We all remember the penultimate game of the 2011 season, where Ryan Roberts’ grand-slam capped off a six-run rally in the bottom of the 10th inning, giving the Diamondbacks a 7-6 game. But the “winning” pitcher that day? Micah Owings, the man who allowed the Dodgers to score five runs in the top of the frame – one of the worst relief performances of all time. By all objective standards, the win should have gone to Jarrod Parker, who earlier in the game had thrown 5.2 scoreless innings. In his major-league debut, no less.
Losses are no less arbitrary. On June 25, 1999, Randy Johnson tossed a dominant complete game against the Cardinals, striking out 14. The Game Score was 85, a figure reached only a handful of times by a D-back since the end of 2019. But it was a 1-0 loss, so the Big Unit got the L. Ten days later, against the same opponent, he tossed eight innings and fanned a dozen. Another 1-0 defeat, Johnson taking the decision. Oh, and the start in between? Eight innings, seventeen strikeouts and no walks. A 2-0 loss, and yet another L. These formed part of a four-game streak where Johnson had a 1.41 ERA, with a K:BB ratio of 54:10 across 32 innings… and went 0-4.
The most egregious loss in D-backs history, however, might belong to… Scott McGough? On May 16, 2023, he came in to pitch extra innings against the A’s in Oakland. He stranded the Manfred Man in the 10th. He did it again in the 11th. Finally, in the 12th, the ghost runner scored – without the ball leaving the infield. But because the Arizona offense had failed to score their Manfred Man, going 0-for-9 with a runner in scoring position during the extra innings, McGough took the L, for that unearned run. That was despite delivering a Win Probability for the game of +42.4%. That’s the highest ever WP for an Arizona pitcher who was given the loss.
So, it’s high time to re-evaluate wins and losses. I therefore submit this modest proposal (which unlike Jonathan Swift’s, does not involve dietary changes). Decisions can now go to any player on the roster, hitter or pitcher. The metric to be used is Win Probability. We first decided whether the hitting or pitching was most responsible for the decision. Once that has been done, then the player with the highest (for a victory) or lowest (in defeat) WP in that category will get the W or L by their name. Tally these up over the course of a season, and we can see which players, on both sides of the ball, are the biggest winners and losers.
To start, we need to find the cut-off point to decide whether a game should be ascribed collectively to the hitting or the pitching. The two are interlinked. A contest always starts with a 50% chance of victory: a win ends at 100%, a loss at 0%. So in triumph, the hitting and pitching WP will always add up to +50%; in disaster, they add up to -50%. So if you know the result and pitching WP, you can work out the hitting WP. I looked at all 2,430 regular season games played last year. The average team pitching WP in those was +27.53%. That means the average hitting WP in them was +22.47%. For losses, the pitching average was -22.45%; hitting -27.55%.
It’s interesting that they are almost symmetrical, but a little skewed. The easy thing to do would simply be to ask for each game, did pitching or hitting have the greater WP, effectively setting the cutoff at +25.0%. That wouldn’t be too far from what the number crunching above showed. But since I did the math, we might as well use the derived figures. So here are the rules. In a win, if pitching WP is +27.5% or higher, pitching gets the W. In a loss, if pitching WP is -22.5% or lower, pitching gets the L. Otherwise, it goes to hitting. Then, the actual letter goes beside the player in that category, with the best or worst individual WP as appropriate.
Let’s take a look at a couple of examples. the Opening Day loss. Arizona’s pitching WP was -37.8%, so they get the decision. The worst pitcher by WP on the day was Zac Gallen (-31.0%). He therefore gets the loss – in line with the old-school metric. But let’s look at the win in the home opener. The pitching WP there was +13.5%. That’s below the +27.5% threshold, meaning victory goes to the hitters. The best Win Probability on the Diamondbacks that day was Corbin Carroll’s +28.6%, so it’s Carroll who gets the W by his name. Doing the same for all the Arizona games to date, here’s what we get.
- Thu, March 26, L 6-8 @ Dodgers. Pitching WP -37.8%. L = Zac Gallen (0-1)
- Fri, March 27, L 4-5 @ Dodgers. Pitching WP -28.2%. L = Ryne Nelson (0-1)
- Sat, March 28, L 2-3 @ Dodgers. Pitching WP -21.5%. L = Nolan Arenado (0-1)
- Mon, March 30, W 9-6 vs. Tigers. Pitching WP +13.5%. W = Corbin Carroll (1-0)
- Tue, March 31, W 7-5 vs. Tigers. Pitching WP -17.6%. W = Jose Fernandez (1-0)
- Wed, April 1, W 1-0 vs. Tigers. Pitching WP +73.0%. W = Zac Gallen (1-1)
- Thu, April 2, L 2-17 vs. Braves. Pitching WP -38.7%. L = Ryne Nelson (0-2)
All told, Arizona’s hitters are 2-1, while the pitchers are 1-3. Given the team is ranked 12th by OPS, and 27th by ERA, that feels about right! I’ll keep an eye on the figures as the season progresses, and probably give weekly updates on the win totals.
