Phillies Nation

Statistical Analysis

What should be expected of Zach Eflin and Vince Velasquez in 2020?

Zach Eflin is hoping to win a job in the Phillies rotation. (Kyle Ross/Icon Sportswire)

The battle for the final two spots in the Philadelphia Phillies rotation is mostly between three starters, with the odd man out likely relegated to bullpen duty. After taking a look at Jake Arrieta and Nick Pivetta, it’s time to examine Zach Eflin, Vince Velasquez and a potential wild card for the last spot in the rotation.

Zach Eflin

Eflin’s tenure with the Phillies has been a bumpy one, alternating month-long stretches of dominance with equally long periods in which he resembles a replacement-level pitcher.

His 2019 was no different, a story of three mini-seasons beginning with a tantalizing start that found him among the ERA leaders in the first third of the season, followed by a horrendous middle period in which he was demoted to the bullpen and concluding with a strong finish in which he returned to his favored sinker and seemed to solidify his place in the 2020 rotation.

These three distinct phases were accompanied by noticeable changes to his approach in each two-month stretch:

At the beginning of the season, he favored the “fastballs up” approach preached by former pitching coach Chris Young, and seemingly had great success with it. Then he began to lean on his slider more and suffered disastrous results. Once he returned to the rotation, it was apparent that he had made the decision to use his sinker more, and the on-field results swiftly improved.

The simple solution to Eflin’s inconsistency seems to be embracing his role as a groundballer and predominantly featuring his sinker. Unfortunately, the underlying numbers from these periods tell a different story and caution against such an easy fix:

First 2 months 3.02 4.42
Second 2 months 6.75 5.44
Final 2 months 3.08 4.87

His FIP – Fielding Independent Pitching, a measure that removes batted ball luck and focuses on things the pitcher can control such as strikeouts, walks and home runs – indicates that he was roughly the same pitcher using his 4-seam-dominant mix in the first third of the season as he was when he relied on the sinker more in the final third of the season. During both periods his ERA vastly outperformed his FIP, suggesting that neither single-minded approach was truly destined to work for him long-term.

The problem the 6’6” righty faces appears to be a lack of identity as a pitcher. He’s stated that he’s more comfortable as a sinker-baller, yet he has only induced groundballs at a league average rate throughout his career. The best season of his career by most metrics was 2018, during which he used his 4-seamer more than any other season, threw his sinker less than he has in any other season and piled up a career high in strikeouts per nine innings. This strategy doesn’t appear sustainable for him over a full season, however. In 2018 he was visibly worn down in September and in 2019 he complained of fatigue in June, right around the time he de-emphasized his 4-seamer.

To find that elusive, consistent success, Eflin needs to strike a balance between his fastball and sinker. Favoring either one at the cost of the other has limited his his ceiling so far in his career. Until he strikes that balance, he is likely to remain an enigma and a borderline No. 4 starter for the foreseeable future.

Vince Velasquez

Velasquez is perhaps the most well-known commodity on the staff. Teased by the ghost of the oft-referenced 16-strikeout complete game he threw against the San Diego Padres in 2016, there’s been seemingly perpetual hope that he could harness his explosive stuff and become a consistent power arm in the rotation. Instead, year after year, Vinny has shown that he simply is what he is: a No. 5 starter who can give the team five decent innings, but struggles if asked to do anything more than that.

Last season he had a run from July until the end of August where in six of seven starts he went at least five innings and surrendered no more than three runs. He had a similar run of starts from June to August in 2018. These stretches of basic competence from Vinny occur annually – the problem is that he doesn’t appear to be capable of maintaining them or improving on them. His serviceable stretches almost always end abruptly with catastrophic starts like the one in Miami last August in which he coughed up a seven-run lead in a single inning.

The difference between the passable version of Velasquez and the one that looks out of place in a major league game is simple and obvious: keeping the ball in the park. In his two best seasons, 2016 and 2018, Velasquez posted the two lowest HR/FB rates of his career. In his two other seasons, 2017 and 2019, he posted the two highest. Already a heavy flyball pitcher, the juiced ball from last season most likely hurt Velasquez more than any other pitcher on the staff (although Pivetta, Arrieta and Nola also set career highs in HR/FB rate).

Hitters too often know what’s coming when Velasquez is on the mound, which can lead to these struggles with the long ball. While his fastball is very good, he is far too reliant on the pitch; among starters who threw at least 2,000 pitches last year Velazquez’s 62% fastball usage was tied with Antonio Senzatela for tops in the league. Having only one plus pitch makes putting hitters away difficult, and a common pattern emerged during Velasquez’s starts which involved batters fouling off an endless stream of 4-seamers, driving up Velasquez’s pitch count and forcing him out of games before the sixth inning. Indeed, this was so bad that he tied for the highest percentage of strikes that were the result of foul balls.

  Percentage League rank
Fastball usage 62.0 t-1st
Fouls/strikes 32.9 t-1st
Total fouls 20.9 t-4th

Ranks are among pitchers who threw 2,000+ pitches.

It’s probably too much to expect him to develop a plus secondary pitch at this point in his career but mixing it up more could at least keep batters off balance. In the best season of his career – 2016 – Velasquez used his curve and change-up a combined 27.3% of the time. That number had fallen all the way to 12.2% by the end of last season, as he’s used his curve less and less each season and eschewed use of the change-up altogether. Not coincidentally, 2016 was also the season in which his fastball was most effective in two-strike counts with a 26.3% putaway percentage, which is the rate at which a two strike pitch results in a strikeout. For comparison’s sake, the putaway percentage of his fastball in 2019 was 19.2%.

If Velasquez continues to be a one-pitch pitcher, his future most likely lies in the bullpen, where he’s already flashed some potential.

The Wild Card

Of course, no pitcher from this group will have a more highly-anticipated 2020 season than somebody who has yet to touch a ball in a major league game: top pitching prospect Spencer Howard. The expectation is that by the end of the season, Howard will be headlining the rotation alongside Aaron Nola. But what can be expected from Howard in his rookie season, and can he make the rotation out of spring training?

It wouldn’t be unprecedented for Spencer Howard to begin the season in the majors after never pitching in Triple-A: Chris Paddack did so just last year for San Diego. In fact, Paddack represents a realistic example of what Howard could be in his rookie season. He was named the No. 35 prospect in baseball by MLB Pipeline before the 2019 season; Howard was just listed 34th overall by the same scouting service. Paddack sports a devastating change-up and a mid-90s fastball that touches the upper 90s, a similar arsenal to the one that Howard possesses:

Paddack’s fast track to the majors featured domination of High-A before ending the 2018 season with 37.2 innings at the Padres Double-A affiliate in San Antonio. His next step was making the Padres major league roster, and he immediately looked right at home as a capable starter at the top level. His numbers for the season: 26 starts and 140.2 innings with a 3.33 ERA, a 3.95 FIP and a 26.9% strikeout rate.

Howard’s path mirrors Paddack’s: overwhelming hitters in High-A before dominating in 30.2 innings at Double-A, then coming to Spring Training with an outside chance at a spot in the rotation. If he looks the part in Clearwater over the next month-plus, there’s an outside chance Howard could follow in Paddack’s footsteps.

Phillies execs and manager Joe Girardi have already spoken about limiting his innings, so reaching 25 starts with the big league club seems unlikely. When he is eventually called up, however, Howard’s production could resemble what San Diego’s young starter did last season.

The most likely outcome, of course, involves Howard beginning the season in Lehigh Valley after Spring Training, and moving up after a couple months in Triple-A, but making the team out of camp isn’t outside the realm of possibility, and who wouldn’t want to see that?


  1. Matt Klentak: It’s Time To Play In October
  2. 34 Numbers To Remember: Roy Halladay’s Incredible Career
  3. Joe Girardi Hopes That David Robertson Will Pitch In 2020
  4. Seranthony Dominguez: ‘I Want To Be Ready For Opening Day’
  5. Bryce Harper Gives Nuanced Take On Potentially Trading For Kris Bryant
  6. Andy MacPhail Hopes Phillies Will Exceed Luxury Tax In 2020
  7. Phillies Nation Roundtable: Bold Predictions For 2020
  8. Matt Klentak Says Odubel Herrera Will Have To Earn Any Future Opportunities
  9. The Phillies Path To One Of The Wild Cards Won’t Be Easy Either
  10. PECOTA Predicts Phillies Will Finish With Losing Record

Phillies Nation has been bringing Phillies fans together since 2004 with non-stop news, analysis, trade rumors, trips, t-shirts, and other fun stuff!

Browse the Archives

Browse by Category

Copyright Phillies Nation, LLC 2004-2022
Not Affiliated with Major League Baseball or the Philadelphia Phillies

To Top