Connor McCullough
Right-Handed Starting Pitcher
6´1´´
185 pounds
Age: 26
2024 South Side Sox Top Prospect Ranking 70
2025 South Side Sox Top Prospect Ranking 83
2025 High Level Birmingham (AA)
Age relative to high level 0.3 years
SSS rank among all right-handed starters in the system 9
Overall 2025 stats (ACL/High-A/AA) 0-4 ⚾️ 13 starts ⚾️ 42 IP ⚾️ 3.43 ERA ⚾️ 0.952 WHIP ⚾️ 39 K ⚾️ 10 BB ⚾️ 0.8 WAR

Connor McCullough went undrafted out of Kansas State University, and it’s a bit mystifying as to why. No, his numbers weren’t electric (career 10-9, 4.63 ERA, 1.389 WHIP) but he took the ball regularly as a junior and senior, pitching in the Big 12. It seems that every year we see players selected on more of a hunch than that.

At any rate, less than two weeks after the 2022 draft, the White Sox had snapped up McCullough and got him an inning of work in Arizona — where the lifetime starter earned a save in his pro debut.

It was a tale of two seasons in 2023 for McCullough. The good was his outstanding seven-start run against younger (1.4 years) competition at Kannapolis, which included a remarkable seven-inning no-hitter that highlighted his great May. Throughout that month, he logged 24 innings with a stellar 1.13 ERA, demonstrating consistent effectiveness on the mound. McCullough’s control and command were evident from his low walk totals; that month, he issued just two walks over the 24 innings pitched. McCullough displayed an impressive strikeout ability as well. He recorded 27 strikeouts in May as well, showcasing his knack for generating swings-and-misses, with a strikeout rate of 31.7%

Following his miracle month, McCullough was promoted on May 31 to the Dash. In his first start with them, he pitched four innings and allowed four runs. Looking at McCullough’s performance in Low-A overall and why he earned that promotion: He maintained an impressive 2.17 ERA. That 31.7% K-rate was coupled with a miniscule 5% BB-rate: A 26.6% rate difference was definitely a clear sign Low-A was a little too easy for him.

The righty did struggle overall against age-appropriate competition in High-A, with a propensity to give up big hits while still maintaining reasonable walk and hit totals. Another factor in McCullough’s favor in spite of a scary 5.33 ERA is his ability to shoulder a heavy workload: He threw no fewer than 59 pitches in any Dash outing and went at least four innings (for some arms, the MAX that would be allowed them) in all but two of 16 High-A starts.

The 2024 season ended up a lost one for McCullough, who only lasted until the end of April before getting shelved with injury — serious enough to warrant 60-day IL status that took out his season. The promising righty ended up with 100 innings fewer than he threw in 2023, which is never the direction you want to head on your way to the majors.

Last year, McCullough missed the first half of the season while still rehabbing from his 2024 injury, so it marked a second straight season for him losing significant time. That said, McCullough was excellent in his second-half work, ranging from rehab starts in Arizona, through Winston-Salem, and back to Birmingham. His ERA held steady from his strong 2024, while winnowing his WHIP to less than 1.000. And Double-A was still age-appropriate for him, so in theory McCullough is still on track to move upwards in the system and to the South Side.

Depending on how gingerly the White Sox want to handle McCullough, he may go back to the Barons for a third tour; after all, he hasn’t yet compiled even a half-season of starts there. However, it’s not out of the question he gets the call to Charlotte to start 2026.

2026 Top 100 Prospects no longer in the system
15. Peyton Pallette, RHRP (lost to Cleveland in the Rule 5 draft)
31. Gage Ziehl, RHSP (traded to Boston on Feb. 1, 2026)
43. Ronny Hernandez, C (traded to Boston on Nov. 18, 2025)
51. Drew Dalquist, RHRP (declared free agency, signed Triple-A deal with San Diego Padres)
66. Andre Lipcius, 1B (declared free agency)
84. Caleb Freeman, RHRP (declared free agency)
90. DJ Gladney, RF (declared free agency, signed Double-A deal with New York Yankees)
98. Luis Pineda, C (declared free agency)