CHESTER, Pa.— The Philadelphia Union continue to make bold moves heading into the 2026 season as the club has announced the sale of Union veteran left back Kai Wagner to England’s Championship side Birmingham City.
Wagner, 28, moves to the second-tier English club for an undisclosed transfer fee on a 2.5 year contract. Birmingham are in the midst of their season and sitting at 14th in the table.
The news of the outgoing sale broke on December 31st by José Nuñez, and finally gives Wagner his move to Europe as it seemed for years that rumors during the season and offseason were always out there about him departing the Union.
“The contributions Kai has made to this club over the last seven seasons have been nothing short of exceptional,” said Philadelphia Union Head Coach Bradley Carnell in the club’s press release. “He has been a crucial piece of this team’s success over the past seven seasons, and we remain grateful not only for his consistent dedication and hard work, but his staunch leadership qualities both on and off the field. At this time, we are honoring Kai’s wishes to continue his career in Europe, as he feels this is the right step for him and his family. We wish him all the best and know he will continue to find success.”
In 2023, Wagner famously made the statement that he was going to be leaving Philadelphia at the end of the season, which stoked the fires from the fan base to campaign to pay Kai. The Union however, did come to terms with Kai and his representation and the club announced that following offseason that Wagner would be back on a new three-year contract through the 2026 season with a club option through 2027.
The move comes during an offseason in which the club has moved off multiple key players. Veteran center back Jakob Glesnes, who after a bounce-back season earned Best XI honors along with Wagner, is off to the LA Galaxy, and last year’s leading scorer Tai Baribo departed for DC United.
Baribo and Glesnes were coming off solid 2025 campaigns and selling them high is good for business, which personally, I tend to agree was a shrewd move. The Wagner deal is interesting, though, for a number of reasons, but ultimately the club did right by the player who wanted to make the move to Europe.
In 2025, Wagner led Philadelphia in minutes played (2,769), assists (11), and key passes (90) as the club lifted their second Supporters’ Shield in club history. Wagner’s 11 assists were the second most by a defender in MLS in 2025, and brought his total to 63 in his seven-year MLS career. The German defender is the only full back since the start of 2010 to earn multiple MLS Best XI honors after previously being named to the team in 2022. He also broke the team record in 2024 for regular season assists, surpassing Sebastien LeToux, and continued to add to that ever since.
Also, the Union were already very thin at the left back position. The club did not exercise the option of left back Isaiah LeFlore, who was loaned to Detroit City of the USL during the end of the summer, and to be fair, did not crack the first team minutes, so it was to be expected.
But with Wagner’s departure, the only players that have true left back experience on the current roster are Nathan Harriel and Frankie Westfield. The latter played most of the 2024 MLS Next Pro season at left back and excelled there during his time, earning MLS Next Pro Best XI. Harriel has played there as well, and would often be used when Kai was unable to go during a match. So it reasons that both will get opportunities there barring an incoming player during the upcoming transfer window, which one can assume the Union will be exploring their options now.
Also, it will be interesting to see who now fills for the void for Wagner’s 63 career assists on the current roster. Quinn Sullivan recovering from his ACL surgery, there will be an opportunity for players both current and incoming to step up and help create chances in the attack. Milan Iloski was taking corner kicks in situations later in the season, instead of it being solely Wagner’s job, and did well.
But regardless, the Union gave Wagner the opportunity that he had wanted with a move overseas to Europe in a top 5 league, which again, they did right by the player. Meanwhile, the Union kept going with their mission with getting younger and bringing in talent that fits with their philosophy.
In addition to his contributions on the field, it is worth noting Wagner’s efforts off the field with the community. He was very involved in the Union’s Kick Childhood Cancer and Fearless 43 initiatives, visiting and supporting children battling cancer. In 2024, along with Leon Flach and Oliver Semmle, ran a youth soccer camp with some of the proceeds going to the Kisses for Kyle organization. He made hospital visits and had special relationships with the children and their families.
It will be an interesting couple of weeks as the squad prepares for its preseason and with the international transfer window to see how Bradley Carnell and the Union front office choose to address these recent moves. But in that same breath, it is fair to say thank you to Kai Wagner for all the incredible plays and moments that he has brought to the Philadelphia Union throughout the years.
Jillian Almoney contributed to this article.
Main article photo credit: Philadelphia Union
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