The free agent market for starting pitchers is going to be driven by a pair of southpaws: former Arizona Diamondbacks’ lefty Patrick Corbin and former Houston Astros’ control pitcher Dallas Keuchel. A quick glimpse at these players’ aggregate performance over the past three years seasons tells a very similar story:
- Both have pitched between 515 and 550 innings
- Both have a FIP between 3.70 and 3.80
- Both have an ERA between 3.75 and 4.05
- Both have a walk rate between 7.0% and 7.5%
As is the case with most things in life, however, it is not about the destination, but the journey for these two players. Keuchel has arrived at that aggregate FIP over the past 3 years as follows:
Corbin’s FIP by year, meanwhile, has been much more erratic:
These pitchers arrived at their aggregate performance by traveling two very different paths. Keuchel traveled the path of consistency, while Corbin the path of exponential improvement year-over-year.
And, to top off this difference in variance, Keuchel has pitched 145 or more innings in every season since his call-up in 2012. Patrick Corbin threw 50.3% breaking balls in 2018 and underwent Tommy John surgery in 2014—causing him to miss all of the 2014 season. While, in this day of baseball, all pitchers are fragile commodities, it certainly appears as though Corbin carries the greater injury risk.
For all of these reasons, baseball fans should pay attention to the Corbin/Keuchel test case. It is a rare opportunity in which we, as outsiders, will see how MLB front offices value a breakout season in a contract year—like the one Corbin put together in 2018. In addition, general managers’ aggressiveness in pursuing either Corbin and/or Keuchel will indicate the direction of their respective Major League franchises.
Before diving deeply into these topics, it is important to note that Keuchel is a year older than Corbin. Therefore, when evaluating the final contract each player gets, average annual value (AAV) will be a better indicator of these players’ values in the market, rather than total contract value.
The difference in the contracts that Corbin and Keuchel sign will give fans an idea of much teams buy a big breakout like Corbin’s. Corbin’s stellar season in 2018—when he finished fourth among all MLB pitchers in WAR—did not happen due to random chance. He threw his slider 3.5% more than he did in 2017, virtually eliminated his changeup from his repertoire, and introduced a curveball—even as the velocity on both his sinker and four seamer dropped by roughly 1.5 MPH. This lead to an absurd 9.2% increase in strikeout percentage—increasing Corbin’s strikeout total from 8.45 K/9 to 11.07 K/9—and a simultaneous decrease in walk percentage by 1.4%. In all, Corbin’s K/BB rate jumped from 2.92 in 2017 to 5.13 in 2018.
Corbin did not get better by osmosis. He made deliberate changes in his approach that led to this improvement.
Yet, there are very-difficult-to-quantify factors that GMs still need to consider. Has the league fully adjusted to Corbin, or will they be able to adjust further and, therefore, hit Corbin harder? Is the decrease in Corbin’s fastball velocity something to be concerned about in the long-term? Is it a signal that he is at risk for injury in the future? Does his high percentage of breaking balls lead to a greater risk of injury? We will be able to quantify—to some degree—the way that GMs answer these questions in the AAV difference between Corbin and Keuchel.
On a larger scale, given the difference between Corbin and Keuchel, fans can better understand the teams that are interested in these two lefties. Teams looking for a true ace willing to dish out cash for risky assets—like the New York Yankees—are most likely going to pursue Corbin with intensity. Risk-averse teams looking for a solid innings-eater will be lining up for Keuchel.