For starters, the performance of starting pitching has changed significantly recently. This chart shows the count of qualified pitchers, their average ERA (not waited by innings pitched), their average FIP and their average WAR.
It’s pretty simple, there are 30 teams in the majors and each team historically has five starters in the rotation, meaning there are 150 starters that have a shot to be qualified. From 2010-2014, roughly 90 starters threw over 160 innings, or on average each team had three qualified starters. In 2017 that dropped to 56 starters, or on average each team had only two qualified starters. However, despite the drop in qualified starting pitchers, their performance hasn’t improved. The average ERA and FIP have gotten worse over time, suggesting that finding qualified pitchers is harder in this new age. That’s one reason why only 25% of qualified starters were worth 2 WAR or less in 2017. Starters that can give their team 160 innings with a decent ERA and FIP have become much more valuable than they were even two years ago.
Unsurprisingly, the number of starters used in a year has gone from 273 in 2010 to 315 in 2017. Part of this is because teams received on average 970 innings from their starters in 2010 but only 890 innings from their starters in 2017. But part of it is that the average starter has gone from throwing 106 innings in 2010 to only 85 in 2017. As a result, teams have gone from using 9 starters on average to using 10.5 starters on average. As more starters are used, the average ERA and FIP has also gotten worse. Things are somewhat better this year, but not by much. According to TruMedia, there are 79 qualified starters in 2018 compared to 73 at this point in 2017. Expect a small increase of qualified pitchers from last year, but probably not a large one. Here's how the numbers look for all starters.
The value of backend starters that can give you a large amount of innings without having terrible results has skyrocketed due to their scarcity. Teams only have so much starting pitching depth. The more starters that they’re forced to use, the more likely that they’re going to get an atrocious performance from somebody. The teams with the best starting pitching are those like the Indians who made it through 2017 using just seven starting pitchers. Having guys like Bundy and Gausman on your roster helps keep the bullpen fresh and ensure teams don’t need to use their AAAA guys as starters.
It’s possible to use FIP to rank starting pitchers from 2010-2017. For each year, we know how many starters each team used on average, so it makes sense to put starters in groups based on the average number of starters used by a team. For example, in 2010, teams used 9.1 starters per year, so we can rank starters from 1 (best) to 10 (worst) based on their FIP. In 2017, teams used 10.5 starters per year, so we can rank starters from 1 (best) to 11 (worst).
When using this method, it becomes pretty clear that there’s a big difference between aces (average FIP of 2.59) and #2 starters (average FIP of 3.28), the second worst starters (average FIP of 5.27) and the worst starters (average FIP of 8.12) and the third worst starters (average FIP of 4.72) and the second worst starters. Aside from those groups there’s roughly a .2 or .3 FIP difference between ranks. Over 180 innings, this is equivalent to roughly 5 runs or half a win. A decent-sized distinction, but not a huge one. Here's how the groupings look.
Using this method, Kevin Gausman consistently (2015-2017) appears to be a #5-6 starter while Dylan Bundy looks to be an outright #6 or even worse. That stated, FIP probably isn’t particularly fair to Orioles starters. FIP presumes that pitchers are fully responsible for all home runs that they allow, but it’s a lot easier to hit a home run in Camden Yards than in the Oakland Coliseum. Fangraphs WAR uses a park factor to take this into account, but FIP does not. So, it probably makes sense to consider Gausman a #4-5 starter. Likewise, Sonny Gray was a 3-4 starter in 2014 and 2015 using this metric, while he dropped to a #8 starter in 2016. But due to pitching in a pitcher friendly stadium, it’s likely he should also have been treated as a #4-5 starter. In other words, these two pitchers are probably closer in value than just looking at their FIPs or ERAs would indicate.
At any given time, there are typically around 40 pitching prospects on top 100 prospect lists. Not all of these pitchers graduate in a given year, but if top prospects had a high success rate, then there would be a lot more than 60 qualified starters. The fact is that the likelihood of a top prospect being successful isn’t great, and therefore the value of a prospect that is successful is high. If top pitching prospects that are ranked struggle to be successful, then pitching prospects that aren’t ranked struggle even more often. It’s highly unlikely that unranked pitching prospects will be successful in the majors. They’ll get a shot because teams need to rely on their minor league system for starters, but they’re probably not going to succeed. Unfortunately, fans don’t remember failed prospects.
Kevin Gausman and Dylan Bundy are likely going to be nothing more than #4-5 starters on the Orioles. It’s possible that another team could successfully develop them and turn them into top of the rotation pitchers. But even #4-5 starters that can pitch a full season have significant value. Their performance may not be great, but these guys can solidify a rotation, ensure that teams don’t need to rely on minor league pitchers with minimal talent and preserve a bullpen. The value of that has skyrocketed over the past few years.
