Sizing Up the Boston Red Sox Rotation

The Red Sox got an ugly 4.95 ERA out of their starting pitchers last season, good for the 11th-worst mark in the league. An optimist might look at the Red Sox’s above-average 4.40 FIP, attribute much of the team’s pitching struggles to bad luck, and expect a rebound in 2020. Combined with a potential rebound year from Chris Sale, the Red Sox rotation entered the offseason with the potential to be an above-average unit with four-to-five legitimate fantasy options in 2020. 

The Red Sox’s rotation was decimated this offseason though, with three of their five primary starting pitchers leaving the team for the 2020 season. Rick Porcello (5.52 ERA, 4.76 ERA) left for the Mets in free agency, David Price (4.28 ERA, 3.62 FIP) was shipped to the Dodgers as a part of the blockbuster Mookie Betts trade, and the final blow was when Chris Sale (4.40 ERA, 3.39 FIP) underwent Tommy John surgery. If you were hoping for a rebound driven by FIP, neither of the remaining starting pitchers (Eduardo Rodriguez and Nathan Eovaldi) posted a FIP significantly better than their ERA.

With arguably the thinnest rotation in the major leagues, the Red Sox have struggled to fill out their starting pitching staff. As a result, many pitchers are likely to see opportunities to start for the Red Sox this year. With that in mind, below is an analysis of the fantasy-relevant Red Sox pitchers, broken down into three tiers. The first five pitchers are listed in order of their likely spots in the starting rotation at the beginning of the season, while the remaining pitchers are listed in order of their expected fantasy value.

Tier One

Tier one is made up of pitchers who are set to stay in the Red Sox rotation for the entire season, barring injuries. These pitchers are the most relevant on draft-day since they are locks to start the year in the starting rotation.

Eduardo Rodriguez

The new ace of this Red Sox staff, Rodriguez pitched well last year, posting a career-best 3.81 ERA over 203.3 innings. Importantly, Rodriguez made three adjustments last season which make him an interesting fantasy option in 2020. One of those adjustments was Rodriguez’s fastball location. 

Rodriguez elevated his fastball more often in 2019, helping drive a career-high 12.83% swinging-strike rate for the pitch. The second notable adjustment that Rodriguez made last season was his pitch mix. Rodriguez decreased his slider usage (his worst pitch by xwOBA in each of the past two seasons) to 4.53% while increasing his changeup (23.62% usage rate last year) and sinker (14.25% usage rate last year) usage. Rodriguez’s changeup is filthy, with a 20.12% swinging-strike rate and a .258 xwOBA. 

As good as Rodriguez’s changeup is, his sinker was arguably even better last season with a .247 xwOBA. Rodriguez’s sinker was also his most improved pitch by most metrics including average exit velocity (84.3 mph) and opponent slugging percentage (.250), and its location is the topic of Rodriguez’s third key adjustment. Rodriguez’s ability to use the entire zone with his sinker in 2019 helped it become one of the best pitches in his arsenal and should allow the pitch to be a solid weapon again in 2020.

In addition to the three adjustments mentioned, it’s also worth noting that Rodriguez is developing a curveball, though it’s unclear how the pitch will factor into his 2020 performance.  Overall, after posting a better-than-average .349 xwOBA on contact and a 24.8% strikeout rate last year, Rodriguez has the potential to post an ERA below 3.50 with a strikeout rate of around 27% if he continues to improve. Based on his arsenal and past performance, Rodriguez’s realistic floor is likely an ERA around 4.00 with a  strikeout rate of around 23%, so he’s a high-upside, somewhat high-floor option heading into the season.

Nathan Eovaldi

Eovaldi struggled in an injury-shortened 2019 season, posting a 5.99 ERA over 67.7 innings. Notably, Eovaldi increased his curveball usage from 4.63% to 17.54% last season, and the pitch showed mixed performance. On the plus side, Eovaldi’s curveball posted an impressive 17.98% swinging-strike rate, good for the best mark in his arsenal by more than 2.5 points. Eovaldi’s spin rate for the pitch was also up from 2182 rpm to 2237 rpm, though the latter rate is still below the 2531 rpm average spin rate for curveballs.

Unfortunately, when hitters did make contact on Eovaldi’s curveball, they hit the ball well. Opposing hitters posted a 14.3% barrel rate against Eovaldi’s curveball last year, helping drive a poor .363 xwOBA for the pitch. The other primary issue regarding Eovaldi’s curveball is one that plagued much of his arsenal: command. 

Eovaldi’s zone rate fell from 48.6% in 2018 to  42.5% last season and combined with his unspectacular 28.5% chase rate resulted in a high 11.6% walk rate. Eovaldi’s unusually poor command may also be one of the reasons why his cutter performed so poorly. His second most-used pitch, Eovaldi’s cutter saw its xwOBA jump from .316 in 2018 to .433 last season as its zone rate dropped from 60.6% to 49.1%. 

Eovaldi’s command looked strong in his spring training outings and his elbow injury may have played a significant role in his command struggles last year. If Eovaldi regains his command in 2020 and continues to emphasize his curveball, then his realistic ceiling is an ERA of around 3.30 with a strikeout rate of around 25%. More likely, Eovaldi will post an ERA of around 3.70 with a strikeout rate of around 23% over about 120 innings.

Martín Perez

Despite looking like a lock to stay in the Red Sox rotation this season, Perez is not a draft day target thanks to his lackluster 4.72 career ERA. That being said, Perez is a pitcher worth monitoring in 2020, and the 28-year-old could be a valuable waiver wire addition for fantasy owners.

Perez’s value is largely tied to how well his improvements from last season translate into 2020. At 18.3%, Perez posted the best strikeout rate of his career last season, largely the result of a drastic pitch mix adjustment.

In 2019, Perez introduced a cutter into his arsenal and threw the pitch a whopping 30% of the time, mostly at the expense of his sinker. After never throwing a cutter in his first seven major league seasons, Perez’s cutter became his most-used pitch last year, one that he threw more than all but six starting pitchers in 2019.

With an 83.8 mph average exit velocity, an 11.5% swinging-strike rate, and a .261 xwOBA, Perez’s cutter ranked among his best pitches in 2019. Although Perez’s 9.8% swinging-strike rate is still far from impressive, his cutter helped improve his ability to limit quality contact 2019. Indeed, Perez’s .332 xwOBA was the best in the league among qualified pitchers, suggesting that his .318 BABIP and 9.5% HR/FB ratio were both higher than what Perez deserved.

When factoring in Perez’s bad luck and strikeout improvements, an ERA below 4.00 is a real possibility in 2020. He may not be a particularly exciting option, but that level of production makes Perez a usable fantasy asset in many leagues and a pitcher worth keeping an eye on for pitching-hungry fantasy owners this season.

Tier Two

Tier two consists of pitchers who are fighting for a rotation spot. Some of these pitchers may start the season as starters and lose their job mid-season, while others are likely to be among the first replacements for those losing their starting jobs.

Ryan Weber

After starting in just 11 of his 42 career major league appearances, the Red Sox appear set to begin the season with Weber as their fourth starter. A sinkerballer, Weber primarily relies on ground balls and soft contact for his production.

For his career, Weber owns a 1.13 GB/FB ratio and a 76% in-play rate, making the Red Sox’s infield defense a key factor in his 2020 performance. Xander Bogaerts is projected to be the only real hole in the Red Sox infield defense, and although the defense isn’t likely to hurt Weber’s performance too much, it appears unlikely to help the pitcher very much either.

Another key factor for Weber this season will be how he adjusts to a full-time starting role. Weber owns a career 5.96 ERA as a major league starter compared to a 4.29 ERA as a reliever and his K:BB drops from 4.10 as a reliever to 2.82 as a starter.

Weber’s reliance on soft contact and lack of solid major league starting experience give him a high bust potential in 2020, so he’s far from a lock to keep his starting job through the year. If everything breaks right for Weber this year then he’s likely looking at an ERA of around 4.00 with a strikeout rate below 20%, so there isn’t much to get excited about from a fantasy perspective, especially when considering that he may lose his starting job midseason.

Brian Johnson

The Red Sox might go with an opener instead of a traditional starter in their fifth rotation spot. If not, Johnson is likely to start the season as the team’s fifth starter after having started 26 games for the Red Sox over the past four seasons. Even so, there’s little about Johnson’s profile that should interest fantasy owners.

Of his three primary pitches (fastball, curveball, slider), only Johnson’s fastball has ever posted a better-than-average xwOBA (.315 last season) in a season. Johnson began featuring his curveball at the expense of his fastball last season, but it’s not clear that such an adjustment will improve Johnson’s performance. Johnson’s curveball did induce ground balls at an arsenal-high 55.4% last season, but the pitch posted a poor .352 xwOBA thanks in part to its 41.1% hard-hit rate and 10.7% barrel rate.

With a career 18.5% strikeout rate and no pitch with a swinging-strike rate above 13%, Johnson is a pitcher who requires soft contact to achieve success. Problematically, no pitch in Johnson’s arsenal posted an exit velocity below 87.5 mph last season. As a result, Johnson is unlikely to be a fantasy asset this season and is likely to lose his starting job relatively quickly.

Collin McHugh

After posting a 6.37 ERA over eight starts, McHugh flourished out of the bullpen for the Astros last season with a 2.67 as a reliever. Even with his struggles as a starter last season, McHugh is likely to see significant time starting in 2020 and is an intriguing fantasy option as a result. 

McHugh increased his slider usage from 23.8% in 2018 to 43.4% in 2019, an adjustment that was made at the beginning of the season and was maintained through McHugh’s transition into the bullpen. With an 84.4 mph average exit velocity and a 17.38% swinging-strike rate last season, McHugh’s slider is an elite pitch. To put it into context, McHugh’s slider was the eighth-most effective pitch by xwOBA in 2018 (min. 220 pitches), and its .221 xwOBA in 2019 was significantly better than average. 

McHugh will likely need to improve one of his curveball, changeup, or cutter to become a fantasy asset as a starting pitcher, but his emphasized slider is very encouraging. McHugh is currently recovering from an elbow injury, but his arsenal will be worth monitoring once the season begins and he starts pitching. Pitcher-hungry fantasy owners should jump on McHugh if he shows improvement in any of his non-slider secondary pitches, especially if (more likely when) the 32-year-old winds up in the starting rotation.

Tier Three

Tier three pitchers are those who have a chance to start for the Red Sox this year, but none of the pitchers in tier three are likely to begin the season in the starting rotation. These pitchers likely need strong performances in the minor leagues or out of the bullpen to force their way into the rotation and are most useful as waiver wire pickups mid-season.

Chris Mazza

The Red Sox are reportedly considering using Mazza as an opener in 2020, so even if he starts then he’s likely only valuable in very deep or AL-only leagues. Still, Mazza offers a two-seam fastball that sits in the low-90s mph and a decent slider, and the 30-year-old has had a successful minor league career with a 3.21 ERA over eight seasons.

Mazza’s ceiling as a starter in 2020 is something around two to three quality innings per start with an ERA below 4.00, giving him some value in the deep leagues.

Tanner Houck

Houck hasn’t had the most impressive minor league career with a 4.08 ERA over three seasons, but the 23-year-old offers an intriguing arsenal. With a strong two-seam fastball that sits in the mid-90s mph, a quality slider, and a developing changeup, Houck has the foundation of what can become a major league caliber pitch mix.

Houck will need to improve his command (3.8 BB/9 last season) and develop his changeup into a quality option for him to stick in the rotation, but he likely has the best chance of any Red Sox prospect to make the team as a full-time starter in 2020.

Mike Shawaryn

Shawaryn had a productive minor league career before getting lit-up last season in the major leagues and at Triple-A, posting a combined 5.45 ERA. Even so, Shawaryn offers a solid fastball, a strong slider, and a developing changeup that combine to make him a potentially viable starter in 2020.

Shawaryn will have to bounce back from his disastrous 2019 season and improve his changeup, but he has the potential to be a lower-end fantasy asset if he earns a starting job in 2020.

Bryan Mata

Mata is just 20 years old, struggles with command (career minor league 4.1 BB/9), and is still in need of a quality third pitch, so he’s likely a year or two away from a call up to the major leagues. Still, Mata is the Red Sox’s top pitching prospect, and if he performs extremely well in the minor leagues this year then the Red Sox may consider seeing what he can do at the Major League level.

As a result, Mata has a shot at a mid-season starting job, and he should be on the radar of fantasy owners if he pitches well in the minor leagues.

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