We take our prospect coverage seriously here at Athlon Sports and Sam Antonacci is a prospect who has exceeded expectations so far in his short time in the big leagues. He was the 140th pick overall and taken in the fifth round of the 2024 Major League Baseball draft and ended the 2025 season as the White Sox’s 11th-ranked prospect. Based on Antonacci’s draft profile, some scouts suggested that he’d eventually develop into a utility player due to his lack of power. However, since being promoted from the minor leagues in mid-April, he’s carved out an everyday role as the White Sox’s left fielder. As the team’s leadoff hitter, he’s been the sparkplug that has catapulted the South Siders to the top of the AL Central division.
The Three-Month Gap — Why the Results Finally Caught Up and What It Means Going Forward
Patrick Gorski-Imagn Images
Through his first 64 MLB games Antonacci has a .362 wOBA and .374 xwOBA, but the gap between the two hasn’t always been that close.
April Through May xwOBA, June wOBA, and the Specific Mechanism That Created the Disconnect
In 42 games from April 15 (the date that Antonacci first burst onto the scene) through May 31, Antonacci compiled an above-average .334 wOBA and a .365 xwOBA. He posted a .275 BA, .731 OPS and a 111 wRC+. However, the .031-point gap between his wOBA and xwOBA suggests that based on his quality of contact, his offensive production should have been even better. His other expected stats from his first 42 games like his xBA and xSLG seem to agree with this premise and they also topped his surface-level stats.
In 21 games in June through Sunday, June 28, Antonacci’s BABIP, and other surface-level stats, caught up and in some cases surpassed, his expected stats. In 86 at-bats during that time frame, Antonacci had a .321 BA and a .921 OPS. In addition, his wOBA, which had consistently lagged behind his xwOBA earlier in the season, was .408, .022 points higher than his xwOBA. He also had a 162 wRC+ in those 21 games.
Antonacci’s ground ball rate has been above average all season, but in his most recent 21 games he significantly pulled more of his batted balls and hit less of his batted balls the other way and up the middle. Ground ball hitters who have low pull rates commonly have lower BABIPs than ground ball hitters who have higher pull rates, and Antonacci’s batted profile change might be a contributing factor to his recent surge at the plate.
The Plate Discipline Profile the Scouts Underestimated
The one constant in Antonacci’s profile since being called up from the minors has been his above-average plate discipline. For the season, he has a 15.1% strikeout rate, 7.8% walk rate, and a .391 OBP.
92nd Percentile Chase Rate, 91st Percentile Whiff Rate, and the Fastball Mastery That Changes the Ceiling Argument
His elite plate discipline is further quantified by his Statcast chase rate. Based on his chase rate, Antonacci is swinging at pitches outside the strike zone less often than 92 percent of qualified hitters in baseball. Opposing pitchers need to throw strikes to try to get Antonacci out.
Many scouts assumed that Antonacci would adapt a utility player’s role based on his expected inability to get around on high-velocity pitches. So far, it’s been the scouts who’ve swung and missed because Antonacci has a .321 batting average against fastballs as well as a .481 SLG and .407 wOBA against four-seamers. Antonacci has an impressive Whiff% against all pitches, but it’s especially low (13.5%) against fastballs.
He has also maintained a relatively high 89 LA Sweet Spot % which is impressive for a hitter with a high ground ball rate. Batted balls hit in the “sweet spot” tend to result in relatively high batting averages.
The Fantasy Case — Add Now, Where He Provides Value, and What to Give Up
Patrick Gorski-Imagn Images
Antonacci has fantasy value in just about every fantasy baseball format.
Waiver Wire Priority, Format Specifics, and the Trade Acquisition Ceiling
Antonacci’s rostership rate is generally high across all formats but he is available in over 50% of Yahoo! fantasy baseball leagues. If you play in a shallow league and he happens to be available on your league’s waiver wire, grab him now!
As an everyday player who regularly leads off, he is a solid three-category producer (BA, Runs, Stolen Bases). His elite plate discipline makes him especially valuable in H2H points leagues where points are deducted for batter strikeouts and points are awarded for reaching base. The fact that Antonacci is multi-position eligible (second base, shortstop, third base and outfield in Fantrax leagues) adds to his fantasy value.
A recent one-for-one trade in a Yahoo! fantasy baseball league had Antonacci being moved for Giants starting pitcher Landen Roupp and another had him traded for Angels starting pitcher Reid Detmers.
Antonacci has certainly outperformed many baseball scouts’ expectations and based on his expected stats and elite plate discipline, his gradual increase in production looks more like growth and not just a hot streak. The only thing missing from Antonacci’s game is home run production but based on his minor league profile, which was to be expected. We’ve only got a small sample size by which to evaluate Antonacci but so far, the scouts who suggested that he had a capped ceiling missed the mark.
Questions About Sam Antonacci, Answered
Who is Sam Antonacci and should fantasy baseball managers add him?
Sam Antonacci has emerged as the White Sox’s everyday left fielder and leadoff hitter after beginning the season in the minor leagues. His expected metrics, plate discipline, and everyday role all point toward sustainable fantasy value, making him a worthwhile waiver-wire addition if he is available in your league.
Why did Sam Antonacci’s production improve in June?
Antonacci’s expected offensive metrics outpaced his actual production through April and May before his surface statistics caught up in June. A higher BABIP and changes in his batted-ball profile, including pulling the ball more frequently, coincided with the improvement while his quality of contact remained strong.
What makes Sam Antonacci’s plate discipline stand out?
Antonacci combines a low strikeout rate with a solid walk rate and an elite chase rate, meaning he rarely expands the strike zone. That approach forces opposing pitchers to challenge him with strikes and has been a consistent strength since his promotion to the major leagues.
What fantasy formats benefit the most from rostering Sam Antonacci?
Antonacci provides value across most fantasy formats because he contributes batting average, runs, and stolen bases while reaching base consistently. His strong plate discipline makes him especially valuable in head-to-head points leagues where avoiding strikeouts and getting on base are rewarded.
