Check Swing Challenge system being tested in Arizona Fall League
It’s one of the great sports debates – was that a swing? Every baseball fan has participated in the discourse at one point or another. You’re watching a game when a pitcher throws, say, a nasty changeup that dives below the zone. Fooled only briefly, the hitter begins to swing
It’s one of the great sports debates – was that a swing?
Every baseball fan has participated in the discourse at one point or another. You’re watching a game when a pitcher throws, say, a nasty changeup that dives below the zone. Fooled only briefly, the hitter begins to swing but checks himself just in time. Or did he? The home-plate umpire can’t tell, calls a ball and the catcher points to the first-base or third-base umpire for appeal. Then fans see multiple camera angles and slow-motion video that the umpire doesn’t, and the debate rages.
Let’s face it, the check-swing call is one of the most subjective in baseball. Major League Baseball is now beginning preliminary testing of technology to gauge whether there is a way to create more clarity on check swings.
Using the same Hawk-Eye technology as the Automated Ball-Strike Challenge system already in place in the Arizona Fall League, the Check Swing Challenge is being used on a limited basis in a proof-of-concept stage at Salt River Field.
Teams will be able to challenge an on-field check-swing call to see if the swing crossed a 45-degree threshold from home plate.
That’s the elevator pitch. Here are more details on the latest review system coming to games at Salt River and why it’s being tested in the weeks ahead.
What is a check swing?
There is no definition for “check swing” in the Official Baseball Rules. The closest thing comes in the Definition of Terms where the first example of a strike is a pitch that “is struck at by the batter.” It’s up to the umpire to decide what “struck at” means. Rule 8.02(c) gets into how managers and catchers can ask for umpire help on “half swing” calls but does not expand from there.
Without official definitions, we’re left in a gray area. Common understanding is that the batter has to “cross the plane” or “break his wrists” in a check swing for it to be a strike, but that’s still at the umpire’s discretion without an official rule to fall back on.
So how would this change?
Under the Check Swing Challenge system, managers and catchers still ask for appeals, and umpires still make an initial call on the field. If players disagree, they can challenge the check-swing call to Hawk-Eye, bringing a replay to the in-stadium video board.
The check swing is called an official swing (and therefore a strike) if the review reveals that the bat exceeds a 45-degree threshold from home plate. Want an easier way to visualize that? The foul line is a 45-degree angle from home. If a right-handed batter swings beyond the first-base line, it’s a strike. If a left-handed batter swings beyond the third-base line, it’s a strike.
📩 CLICK HERE TO SUBSCRIBE TO BEN'S BIZ
How many challenges per team per game?
Each team gets to challenge two check-swing calls per game. If a team uses up those two challenges by the ninth inning, it is granted one additional challenge for the final frame.
Who can challenge?
This is the same as with an ABS Challenge. Only pitchers, hitters and catchers can ask for an official review.
Where will this be first tested?
The Check Swing Challenge will only be used in games played at Salt River Fields at Talking Stick in this year’s Arizona Fall League for now. Salt River serves as the Spring Training home of the D-backs and Rockies. This fall's Salt River Rafters roster is made up of players from those two systems as well as from the Nationals, Twins and Yankees.
Does the Arizona Fall League have a history of testing out potential new rules?
Yes! ABS, pitch clocks, bigger bases, mound visit limits, shift bans – many potential rule changes (both big and small) have been tested in the AFL before they’ve made (or, in some cases, not made) the Majors.
Sam Dykstra is a reporter for MiLB.com. Follow and interact with him on Twitter, @SamDykstraMiLB.
Podcast: New Erie identity, new ballparks, new Top 100
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
How clubs across Minor League Baseball are celebrating PLAY BALL Weekend
PLAY BALL Weekend is almost here, and Minor League clubs have put together an exciting calendar of events to celebrate MLB’s youth engagement initiative. Some clubs are hosting youth clinics or other events in their home ballparks while others are bringing the joy of baseball and softball into the local
Here are the weirdest plays and stats from MiLB in May
Benjamin Hill travels the nation collecting stories about what makes Minor League Baseball unique. This excerpt from the Baseball Traveler newsletter, presented by Circle K, is a mere taste of the smorgasbord of delights he offers every week. Read the full newsletter here, and subscribe to his newsletter here.
Podcast features first-base promotions for Caglianone, Eldridge
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
Cubs' Rojas, Mets' Tong headline May's Minor League Players of the Month
Minor League Baseball announced the Player and Pitcher of the Month Award winners for May in Major League Baseball’s player development system.
Minor League Baseball, Joe Torre Safe At Home partnership enters ninth year
For the ninth year, Minor League Baseball and Joe Torre Safe At Home have teamed up to raise awareness about violence and abuse and to inspire fans of all ages to join them in SAH’s critical work. This year, 63 MiLB teams will participate in an in-ballpark initiative from May
MiLB podcast discusses Anthony, Caglianone at Triple-A
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
These are the greatest Minor League promos happening in June
Benjamin Hill travels the nation collecting stories about what makes Minor League Baseball unique. This excerpt from the Baseball Traveler newsletter, presented by Circle K, is a mere taste of the smorgasbord of delights he offers every week. Read the full newsletter here, and subscribe to his newsletter here.
New playoff format coming to 2025 Dominican Summer League
Minor League Baseball announced the 2025 Dominican Summer League (DSL) season will begin June 2 with Opening Day festivities taking place at the Boston Red Sox Academy in Guerra. The 2025 campaign will also see the introduction of the DSL Cup, a new playoff format that will see 16 DSL
Debating best Minor League home caps on podcast
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
The Omaha Storm Chasers' 'Take Meow-t' cat night included a Litter Box Sundae
Benjamin Hill travels the nation collecting stories about what makes Minor League Baseball unique. This excerpt from the Baseball Traveler newsletter, presented by Circle K, is a mere taste of the smorgasbord of delights he offers every week. Read the full newsletter here, and subscribe to his newsletter here.
Boston's Triple-A affiliate throws birthday bash for Roman Anthony
With all the hype that has surrounded Roman Anthony over the past two seasons, it’s easy to forget how young he really is. MLB's No. 1 prospect played 70 games at the highest level of the Minors before he could order a beer. But he can now. Roman Anthony turned
Friendly foes, 2024 first-rounders Moore and Caglianone trade first Triple-A homers
For years, Christian Moore and Jac Caglianone laced up their cleats against one another in the SEC. A rivalry that spanned Florida, Tennessee and other landmarks across the South moved to Salt Lake City this week as the Royals and Angels' top prospects got simultaneous Triple-A promotions. So it was
Phillies' Moore, Fausnaught join MiLB podcast
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
Red Sox prospect rips double THROUGH Fenway-esque scoreboard
Red Sox No. 4 prospect Franklin Arias, an infielder for High-A Greenville, REALLY didn’t want to let visiting Asheville score any runs in the top of the eighth inning on Friday night. With runners on first and second base in the bottom of the fourth, Arias showed he apparently held
April's hottest hitting prospects -- one for each organization
The Minor League season is a month old and several of the game's best hitting prospects are off to fast starts. Red Sox outfielder Roman Anthony is tearing up Triple-A (just like he did at the end of last year), Padres shortstop Leo De Vries is leading the High-A Midwest
Check out the best -- and wackiest -- Minor League promos happening in May
Benjamin Hill travels the nation collecting stories about what makes Minor League Baseball unique. This excerpt from the Baseball Traveler newsletter, presented by Circle K, is a mere taste of the smorgasbord of delights he offers every week. Read the full newsletter here, and subscribe to his newsletter here.
Orioles' Honeycutt joins The Show Before the Show
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
MiLB podcast coming LIVE to a Somerset this June
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
New ballparks highlight 2025 MiLB road trip stops
Benjamin Hill travels the nation collecting stories about what makes Minor League Baseball unique. This excerpt from the Baseball Traveler newsletter, presented by Circle K, is a mere taste of the smorgasbord of delights he offers every week. Read the full newsletter here, and subscribe to his newsletter here.
Minor League Baseball partners with TruGreen
FRANKLIN, Tenn. -- TruGreen, the nation's leading lawn care treatment provider, is proud to announce a groundbreaking partnership with Minor League Baseball that includes activations across all 120 clubs, a makeover of the home dugout in each market, sponsorship of select MiLB team grounds crews, and a new initiative called
Podcast explains why the Syracuse Mets are looking for Jim Morrison
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
Dash im-prom-tu promo and Mets' Suero joins the podcast
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
Minor League Baseball partners with Circle K
Minor League Baseball announced a new national partnership with Circle K, which will see the convenience store giant become the “Official Convenience Store of Minor League Baseball.” During the 2025 season, the Circle K brand will be integrated into the MiLB in-stadium experience through in-game video board assets at most
These 15 moments led to season No. 15 of Minor League road trips
Benjamin Hill travels the nation collecting stories about what makes Minor League Baseball unique. This excerpt from his newsletter is a mere taste of the smorgasbord of delights he offers every week. Read the full newsletter here, and subscribe to his newsletter here.