Freddy Adu landed with the Philadelphia Union after a journey through the European ranks. (Drew Hallowell/GETTY IMAGES)

The last time Freddy Adu stepped onto a soccer field for a match involving D.C. United, Ben Olsen, Alecko Eskandarian and Josh Gros were teammates and Peter Nowak was the coach with whom he had clashed over playing time. The Philadelphia Union didn’t exist, nor did PPL Park, and United was an annual lock for the MLS playoffs.

Adu was still a teenager from Potomac, in his third and final season with United before relocating to Salt Lake City, Portugal, Monaco, Portugal again, Greece and Turkey.

Almost five years have passed, and after a backwater journey through European soccer and a ceremonious return to MLS this summer, Adu might face the club that launched his wildly hyped career at age 14 for the first time. The teams will clash in a crucial late-season match Thursday night in Chester, Pa.

Adu, now 22 and in his eighth professional year, missed last weekend’s game at Sporting Kansas City with an ankle injury. On Wednesday, though, he said: “It’s good. I’ve been training on it the last couple days. It’s a little bit sore, but that’s expected.”

Although Adu was in MLS for another season after United traded him in late 2006, he didn’t cross paths with his boyhood team. Playing for Real Salt Lake in ’07, he didn’t appear in either of the clubs’ meetings: He was with the U.S. under-20 World Cup team for the first match between them in June, and by the time the teams met again in September, he’d been transferred to Benfica in Portugal.

This year, Adu didn’t join the Union until after the sides had already played in both a U.S. Open Cup preliminary game and a regular season match at RFK Stadium.

“There is a bit of emotion there,” Adu said of possibly playing against his former club. “I had an amazing [experience] with D.C. United. I grew up watching D.C. United and also having a chance to play for D.C. United. Every time I go back [to Washington] with the national team, the fans always show me great support.

“Definitely emotional for me, but once you step out on the field, right now I am a Philadelphia Union player trying to help my team.”

Much has changed since Adu and United were in the same building. The teenage sensation who once attracted worldwide attention with his exciting footwork and prominent endorsement deals is seeking stability after a turbulent odyssey.

He fell short of expectations that, in his defense, weren’t of his doing and were unattainable. (“The Next Pele!” was a common theme.) But he also failed to impress one coach after another and, for much of his time overseas, was relegated to the bench or street clothes on game days. Before joining Philadelphia, he was toiling in Turkey’s second division.

Adu had a year remaining on his contract with Benfica – which had loaned him to four clubs over four years – when he was allowed to leave. The move to the Union reunited him with Nowak, with whom Adu had a testy relationship in Washington. They did, however, grow to understand each other while Adu played for Nowak on the U.S. under-23 national team and 2008 Olympic squad.

And when Adu became available this summer, Nowak was comfortable resuming their partnership.

Adu’s ties to Philadelphia also reach the front office, which features his former United teammates Eskandarian and Gros. The Union’s roster features another ex-colleague, midfielder Brian Carroll.

Olsen, now United’s coach, played in the midfield with Adu and, together in 2004, they teamed to win the organization’s fourth MLS Cup.

“It’s good he’s back in MLS,” Olsen said of Adu, who has made six appearances with four starts and one goal. “I always have, and always will, wish the best for Freddy’s career.”

Adu’s presence Thursday won’t stir memories for United’s current crew. Midfielder Clyde Simms is the only holdover from Adu’s final D.C. game – the 2006 Eastern Conference final against the New England Revolution at RFK.

For both United and the Union, the critical late-season match will overshadow the reunion. With 3½ weeks left, United (9-8-11, 38 points) is poised to pass Philadelphia (9-7-13, 40) in the cluttered MLS standings and enhance its playoff chances. While a top-three finish and automatic berth are within reach for both sides, missing the postseason altogether is also possible.

“This game could change a lot of things as far as the playoffs,” Adu said. “It definitely has a playoff feel to it. This is crunch time.”