In recent weeks, I've highlighted a couple of relievers, Ian Kennedy and Collin McHugh, as two players the Sox should target to improve their bullpen heading into 2020. As we sit here in the aftermath of SoxFest weekend, the bullpen still looks to be the weakest link for the upcoming squad. Absent any additional external reinforcements, the organization appears to be of the mindset that there will be significant bounce backs from internal options. Now, this certainly could be the case, however, as we have seen in recent years, bullpen volatility is something that cannot be avoided. The Sox do have several intriguing options at both the Major League and minor league levels that could help them outperform projections and improve their likelihood of being a legitimate playoff contender.
Should the 2020 White Sox get bounce-back seasons from in-house options, the complexion of the upcoming season could drastically change. Now, there is a high level of risk with many of the players that comprise this group of bounce-back candidates. That risk comes in the form of injury, underperformance, and in some cases, both.
Kelvin Herrera represents perhaps the most important of these candidates, largely due to his status as a formerly premier late-inning reliever and his contractual status with the club. Herrera's first season on the South Side was an unmitigated disaster as he posted his worst ERA since his brief two-inning call up in the 2011 season. Herrera was hampered by back issues for much of the season that appeared to take a toll on his performance. He posted the highest FIP (4.58) of his career due to career-worst BB and HR rates.
From a velocity standpoint, Herrera averaged 96.3 MPH on his four-seam fastball, continuing a gradual decline for the 30-year-old reliever. However, this still ranked in the 80th percentile of all pitchers in 2019, so the velocity itself isn't the problem. Herrera relied heavily on this pitch in 2019, throwing it the most of his repertoire at 35.4%. The results, however, were not positive. According to Statcast data, he posted an xwOBA of .385 against this pitch. It was accompanied by the highest average Launch Angle (19 degrees) of his career for which Statcast data is available.
A noticeable change to Herrera's pitch mix in 2019 was the addition of the Don Cooper special, a cut fastball. Herrera threw this offering 11.1% of the time to an average velocity of 91.3 MPH. The newly added pitch had an average Exit Velocity of 90.4 MPH, which was easily the worst of any offering for the reliever. The cutter produced an xwOBA of .336 in 2019. So what am I saying with all this? I think he should probably ditch this pitch. I know Coop loves to get any newly acquired pitcher on the Sox cutter program, but it simply didn't work for Herrera.
It's entirely possible that the addition of this sub-par pitch decreased the overall effectiveness of his four-seam fastball. 2019 saw an xwOBA over 50 points higher against Herrera's four-seamer than any other in the Statcast era. So, would eliminating the cutter coupled with a clean bill of health rejuvenate Herrera and allow him to return to previous levels of performance in high-leverage spots? We ultimately don't know that, but I think it is certainly worth investigating.
Herrera's ability to be a competent, high-leverage reliever again would provide tremendous stability to a bullpen that is littered with question marks. If he can return to a level of performance relatively close to his pre-2018 levels, the trio of Herrera, Aaron Bummer, and the peripheral-defying Alex Colome could quickly become a strength for the team. Also, should Colome falter, Herrera could provide a level of insurance closing out games.
A second bullpen holdover rebounding that would prove beneficial for the squad would be Jace Fry. Fry's 2019 season was marred by an inability to consistently get the ball over the plate for strikes. In fact, he saw his BB rate double in comparison with his numbers in 2018. I didn't major in math during my collegiate days, but I do believe that 7.04 BB/9 is sub-optimal, particularly for a reliever.
Fry had a simply odd 2019 season in which he saw his GB% spike to 57.0% while simultaneously seeing his HR/9 rate go from .70 in 2018 to 1.15 in 2019. The biggest issue for Fry came with his curveball utilization. This has been the second most frequently used offering from Fry during his brief career, and 2019 saw some truly gruesome results. Opposing hitters had no issues with the southpaw's primary breaking ball. It was truly a stark contrast to what we saw in 2018:
Launch Angle (in degrees)
It's obvious that hitters were squaring up the offering with greater frequency last season. What is somewhat puzzling is that Fry saw increases in his velocity and spin rate on the pitch last season, yet the results were on the complete opposite end of the spectrum when comparing it to his 2018 data. Fry's ability to find an effective breaking pitch to compliment his cutter will prove essential to his viability in a bullpen going forward.
Another obstacle Fry will need to overcome is his splits. Jace showed no ability to consistently get RHH out in 2019. For the season, they slashed .235/.368/.445 against him compared to .193/.352/.265 for LHH. The implementation of the three-batter minimum in 2020 could prove problematic to Fry's long-term career prospects if he is unable to get back on track against RHH.
Given the state of the 2020 White Sox bullpen, bounce backs from Kelvin Herrera and Jace Fry would go a long way towards providing stability to a group that has few sure things. If either or both can return to previous levels of production, a group that goes into the season as a question mark could quickly turn into a strength.