FOUR YEARS AGO, Leon Flach signed with the Philadelphia Union with the hopes that it would be a good place to play, develop, and advance his career. It almost seems counterintuitive to think a player would leave a European club to develop in the United States, but that is the route Flach chose with the ultimate end goal of eventually returning home to Europe.

Flach, 24, was born in Houston to German parents who were there for work. When he was a young child, the family returned to Germany. It was there where he developed as a player and eventually broke through with St. Pauli in Hamburg. He came up through the club’s academy and made his first team debut as a teenager in the 2.Bundesliga.

It was also around this time when he looked as if he would be a lock for the U.S. U-20 team, but that never came to fruition after the COVID pandemic forced the cancellation of the U-20 World Cup. But then in 2021, Flach completed the transfer from St. Pauli to the Philadelphia Union where he saw an opportunity with a head coach in Jim Curtin who believed in him.

Looking back, Flach felt it was a smart decision and he got everything he wanted from the experience which included 124 MLS games, 145 total first team games including appearances in the playoffs, Leagues Cup, and CONCACAF Champions Cup.

But following tough seasons in 2023 and 2024 where he had to work through injuries in the final year of his contract and the team failed to make the playoffs, Flach felt it was time to finally return home to Europe for many reasons. He wants to begin climbing the ladder there and the move also allows his family to watch him play on a regular basis – with even his grandmother traveling to watch him play next month after being unable to travel to the United States.

“Every year has been challenging and also perfect in some way,” Flach recalled of his time in Philadelphia. “The first two years were incredible because I played every game. Personally last year, based on how I played, was my best year. It is weird to say because we missed the playoffs, but I was able to play a lot as the No. 6, and also the No. 8. I think I did some good stuff because I was enjoying everything a little bit more than before. In general, Philadelphia was a perfect start for me because I was able to play against some great players, see every stadium, every city. I came when I was 20 years old and played over 140 games. I think that's the best outcome you could imagine. I was and I still am really happy about that - but at some point, it is also time for something new.”

He had multiple opportunities, but the one that stood out was with Jagiellonia Bialystok, the reigning champions of Poland’s top tier Ekstraklassa.

Unlike the prospect of returning to the 2.Bundesliga, Jagiellonia Bialystok offered the prospects of playing in title race, the chance of playing in the current Conference League knockouts, and pushing for a chance to be in the Champions League next year.

“There was almost no time to start thinking about it , just straight up playing again - which is nice,” Flach said. “The whole pressure situation is different because especially for us, every game counts. We play in almost every competition. We just lost in the cup, which is unfortunate, but Conference League, the league, and we have Super Cup in a few weeks.  A lot of high-pressure games where you have to win. If you lose one or two games, you are almost out of the title race. That’s also something I wanted.”

Early signs are promising. Since arriving, Flach has played in all six of Jagiellonia Bialystok’s Ekstraklassa’s games, one domestic cup game, and all four of the club’s Conference League games. Jagiellonia Bialystok is in strong position in the league where it sits third but is only two points behind leaders Lech Poznan, and advanced past Cercle Brugge this week into the quarterfinal of the Conference League.

“It's always important that you feel wanted,” Flach said of his decision to sign for Jagiellonia Bialystok. “It's a different step, but a good step. I really liked that you play for titles here and you have also a different platform to show yourself. If you have like some good games in Conference League against also good teams, it offers you maybe more chances than playing in the second league in Germany.”

“There is the whole thing about the way they play soccer here,” he added. “I was surprised because a lot of teams, even the smaller teams, try to play out of the back. I think the style of play is really possession based actually…It's very physical too, the refs usually letting a lot of stuff go. I thought if I really developed that part of my game, it could also help me make the next step.”

Flach’s early success with Jagiellonia Bialystok also adds further evidence that Philadelphia Union alumni are currently performing very well in Europe. Brenden Aaronson is a starter for a Leeds United team that leads the Championship. Mark McKenzie anchors a Toulouse backline that is top four in goals conceded in Ligue 1. Paxten Aaronson has had a breakout season with FC Utrecht, where he is on loan from Eintracht Frankfurt in the Eredivisie. Former Union homegrown central defender Auston Trusty starts for Celtic, where he played in the Champions League knockouts and will soon win the Scottish Premiership title. Argentine forward Julian Carranza moved from the Union to Feyenoord last year and he scored the winning goal over AC Milan last month in a Champions League knockout.

Flach is well aware of how the other former Union players are doing and he is still in touch with several of them – recently texting with Carranza and Paxten Aaronson to congratulate them on recent successes.

“I was texting a little bit with Paxten because he's obviously close,” Flach said. “With Julian, I was just wishing him good luck and also after he scored his goal, obviously I had to text him. I think the way we played in Philadelphia is really close to how you want to play in Europe. For the majority of the teams, it's intense, transition-based. It's physical, you want to have the ball back, which I think is really like it is in Europe. As soon as you understand what you have to do in defense, you can really showcase your talents on offense - which especially Julian and Paxton are doing because they are great, great players, especially on offense. The way we played, the way we got educated in Philadelphia, really helped all of us a lot.”

What also helped Flach out a lot is that Philadelphia was also active in the CONCACAF Champions Cup and in the Leagues Cup. That allowed Flach to experience playing in hostile environments and against teams that play in difference countries and different leagues. But as he adjusts to life in Poland and in the Conference League, he appreciates the lessons that he learned places such as Central America.

“We just played in Warsaw against Legia Warsaw and that was the most intense atmospheres I ever experienced. That was actually crazy,” Flach explained. “But Mexico and El Salvador, all those atmospheres, I would say are hostile and to already know a little bit how to feel in those moments and also how to react helped me a lot. I think in competitions outside of the league are always the nicest things because you see different things. You play against different teams from different nations. Everything is different.”

But for Flach, a big factor in the development of these former Union players is Curtin who implemented a style that translates well to Europe. Curtin was fired by the Union after failing to make the playoffs in 2024 but has remained in touch with Flach and has offered him encouragement after a strong recent game with Jagiellonia Bialystok.

“He texted me after my first game here,” Flach said of Curtin. “He watched the game and said congrats on a great game. I really enjoy being in touch with Jim because obviously he's probably the person who I'm the most thankful. He gave me the chance to showcase myself every week in, week out. Even when I didn't have good game, he trusted me the next week. Four years with a coach really does something to you. It was a great relationship and I'm really interested in what he's doing next.”