PHILADELPHIA – The Philadelphia Union announced on Monday that the club has signed Union II forward Stas Korzeniowski to a first team contract through 2026, with club options for 2027 and 2028. Korzeniowski joins the Union after spending the 2025 season with Philadelphia Union II in MLS NEXT Pro. The 22-year-old was originally selected by the Philadelphia Union with the 53rd overall pick in the 2024 MLS SuperDraft.
 
Korzeniowski led Union II with 12 goals in 25 appearances across all competitions during the 2025 season. He scored nine goals over his final seven matches, including a brace against FC Cincinnati 2 in the Eastern Conference Quarterfinals and a goal in the Eastern Conference Final against New York Red Bulls II. Additionally, Korzeniowski appeared on the bench as a short-term call-up for Philadelphia Union's match against St. Louis CITY SC on March 22 and made an appearance for a friendly against Liga MX side Atlas FC in June 2025.

As a Quaker, Korzeniowski had a standout career, scoring 32 goals and added 17 assists in 69 appearances over four seasons. In his senior year, he led Penn with 12 goals and 26 points, earning Ivy League Offensive Player of the Year honors and First Team All-Ivy recognition.