The average OPS (On-base plus slugging) in baseball, through June 21, is .708 but the average OPS in the American League is .714 and it’s just .701 in the National League. Why this is important is because it gives us a measure of the overall quality of hitters in each league, including the state of offensive talent across baseball (somewhat). What it is also useful for is measuring just how much of a pitcher’s performance is related to them facing a murderers row of hitters more often than not, or if they are simply not very good right now or at all.
Baseball Prospectus has a statistic called oppOPS (opponents OPS) which is useful for measuring the average quality of opponents hitters and pitchers have faced throughout the course of a season or career. They have another statistics labeled PPF which is centered around 100 and represents the percentage of run scoring that was influenced by the mix of ballparks the pitcher pitched in. Anything over 100 illustrates the percentage above normal run scoring was influenced and the opposite is true.
It would be fair to state Chris Tillman, Ubaldo Jimenez, Tommy Hunter, and even Miguel Gonzalez to a lesser extent have been having horrible or troubling seasons. The flip side of that is most would agree that Bud Norris and Wei-Yin Chen are having a decent season so far and pitchers like Ryan Webb, Darren O’Day, and Zach Britton have been crushing the competition.
The chart below (stats through June 21) helps break down and illustrate the quality of hitters each pitcher, with a minimum of 20 innings pitched, on the team has faced to this point in the season and where they rank at in that regard, as well as how much pitching in their mix of ballparks has influenced the number of runs scored or not scored.
|Name||IP||ERA||FIP||oppOPS (min. 20 IP)||Rank (out of 356 Pitchers)||PPF|
Britton has had a ton of praise heaped on him since he took over the closer’s role from Hunter, and was being praised for his general work out of the bullpen before that, but you can see he hasn’t been facing much stiff competition. He’s near the bottom of the ranks in baseball for quality of opponents faced, which makes it difficult to accurately judge his dominating performances.
Fans have been calling for Jimenez and Tillman to be placed on the disabled list or moved to the bullpen in message boards and on social media for their struggles. As you can see though, they are near the top of the ranks in baseball for facing some pretty challenging hitters and offenses overall. Additionally, they have also spent most of their time pitching in hitter friendly ballparks, as have the majority of Orioles pitchers.
Looking over the statistics for the Orioles pitching staff in conjunction with the statistics of the overall quality of hitters faced we’re able to at least make a determination of whose performance is possibly for real, for better or worse, and whose we should be a bit more patient with.