It is often hard for a hitter to break into the major leagues. It can be even harder to find regular at-bats, and harder still to produce enough to stick around for a while.
Just ask Brent Rooker of the Athletics.
All Rooker did as an amateur player and in the minor leagues was hit. He was a Cape Cod League All-Star after 2016 and won the SEC triple crown as a redshirt junior at Mississippi State University in 2017. The Twins drafted him 35th overall in the 2017 draft and Rooker raked to a .269 / .366 / .543 triple-slash line and bashed 102 home runs across five minor league seasons.
A pandemic-season callup in 2020 was cut short after just seven games by a broken forearm caused by a hit-by-pitch. Rooker spent most of 2021 in Triple-A (142 wRC+) and didn’t hit enough (91 wRC+) in a late-season big league tryout.
He was traded to San Diego just before the beginning of the 2022 season but again did not make the Opening Day roster. He played in only two games for the Padres that season, again spending most of the season crushing Triple-A (1.044 OPS). He was sent to Kansas City in a deadline-day trade but got just 29 MLB plate appearances down the stretch that season.
The Royals removed him from their roster as part of early offseason house cleaning and Rooker, finally able to choose his destination, headed to the A’s in search of an extended big league shot in 2023.
After two seasons of consistent playing time as the A’s primary DH, he’s produced 69 combined homers and 181 combined RBI. By wRC+, Rooker’s 146 mark the past two seasons ranks 10th in MLB, just ahead of Bryce Harper and Vladimir Guerrero Jr. He’s also picked up an All-Star appearance and won an American League Silver Slugger award.
The home runs just keep on coming for the @Athletics!
Brent Rooker hits one 445 feet for No. 22. 💪 pic.twitter.com/WfNnuJ0Vue
— MLB (@MLB) July 20, 2024
It’s now clear that Rooker has made the most of his opportunity with the A’s. The story of how he did it is one not only of opportunity but also one of growth and development.
The Book on Rooker
Public prospect evaluators considered Rooker a “power-over-hit” prospect, with concerns about whiffs and strikeouts suppressing his outlook. Would he make enough contact to reach his power consistently? Rooker also is in the often dreaded right-handed hitting, right-handed throwing, and below-average corner defender demographic bucket, which also took some shine off his prospect apple.
As he matriculated from through minors to the quad-A gray zone, whiffs were a nagging concern for scouts because Rooker struggled to recognize and make good swing decisions against breaking and offspeed pitches.
On the surface, those concerns seemed to play out in the limited and sporadic MLB opportunities Rooker got from 2020 to 2022 with Minnesota, San Diego, and Kansas City. In 270 combined plate appearances, he hit only .200/.289/.379 (86 wRC+) with a 31.9% strikeout rate and 6.7% walk rate.
Digging a little deeper reveals that a fatal flaw against secondary pitches didn’t drive his weak line:
Somewhat surprisingly, Rooker’s combined work against breaking and offspeed pitches, as measured by wOBA, was in the top third of the more than 600 MLB batters to have at least 50 plate appearances end on those pitch types from 2020-2022. That was likely due in some large measure to his steep, uppercut swing being calibrated well for pitches down in the strike zone.
The bigger issue was that he didn’t make hay against the fastballs he saw.
He would always swing and miss, but for his overall profile to work, he would need to destroy fastballs. His .304 wOBA against fastballs was in the bottom quintile of the 480 batters to have at least 150 PAs end on fastballs in that period. He especially had trouble with fastballs with high velocity and located up in the zone:
Despite his sustained AAA success, it was clear that if Rooker was going to find a foothold at the game’s highest level, he needed to make some adjustments to catch up to and damage big-league fastballs.
Small Changes, Big Differences
Often, when we look at hitters who have finally found their footing in the show, we can point back to an approach or mechanical change that prompted the new level of performance.
Sometimes those are visually obvious things like adding a leg kick or eliminating extra, inefficient movement in a swing. Other times the adjustments can be very subtle and harder to see.
Rooker, in addition to being an excellent follow on social media, is very thoughtful about his craft. He’s able to dissect his approach and simply articulate why he’s trying to do what he’s doing with his swings. In the video link below, he explained the what and why of the adjustments he made in fascinating detail. The whole discussion is excellent, but timestamp 12:10 is where this particular conversation picks up:
“When I’m going bad, it’s almost never my swing as much as it is a getting ready or load issue,” Rooker said in spring training before last season. “If I feel like I’m getting ready the right way pre-pitch and loading the right way, my swing always follows that. I just kind of found something. I use a toe tap as my timing mechanism and I found a little trigger in a way that I was getting to my toe tap that put me on time a little bit more and put me in a better hitting position where my front foot landed.”
Rooker made some subtle adjustments to his pre-pitch setup, added some hand movement in load, and made his toe tap into more of a hover. These adjustments were first flagged by Esteban Rivera in May 2023.
In the video, Rooker credits the adjustments with helping him be on time for fastballs more consistently and giving him more opportunity to stop his swing if he recognized breaking and offspeed pitches out of the zone. The results of these changes speak for themselves:
If we compare this table of the past two seasons with the very first table in this article, you’ll quickly see that the adjustments have allowed Rooker to mash opposing fastballs. (He also maintained a similar level of production against breaking and offspeed stuff.)
Against the fastball group, he’s gained 129 points of wOBA, produced 3.2 more runs per 100 pitches, and cut his whiff rate by 3.4 points. His .433 wOBA against fastballs the past two seasons ranks 4th in the league, behind only Aaron Judge, Shohei Ohtani, and Juan Soto.
What had been a critical weakness has become an overwhelming strength.
As you might expect given those overall figures, Rooker has closed his deficiency against plus velocity and he’s made some other subtle adjustments that have helped with holding his own against elevated fastballs:
In each of the split categories above, Rooker has added at least 114 points of wOBA, chopped at least 10 points off his whiff rate, and gained at least 235 points of slugging compared to his first three big league seasons.
Chasing out of the strike zone (30th percentile in 2024), whiffs (5th percentile), and strikeouts (10th percentile) are still a major part of his game. But, he shaved off enough of the rough edges and unlocked his swing to allow his prodigious power to play. Now, thanks to an extended opportunity and developing into one of baseball’s most productive sluggers, he’s eligible for an arbitration raise for the first time and an interesting candidate for a contract extension.
Photo by Rich von Biberstein/Icon Sportswire) | Designed by Aaron Asbury (@aarongifs on Instagram)