The 29-year-old, who left Germany's VfL Wolfsburg at the end of last season, hopes to play his way back into contention for a spot on the U.S. World Cup roster.
After appearing in two of the first three qualifiers last September, he was dropped by coach Gregg Berhalter and has not been selected for the national team since. Berhalter said the U.S. employed a high defensive line that Brooks was unfamiliar with at Wolfsburg.
Brooks played for Hertha Berlin (2012-17) and Wolfsburg from 2017-22. He scored a tie-breaking goal in the 86th minute against Ghana in the group stage of the 2014 World Cup and has three goals in 45 international appearances.
He becomes the 11th American on a Champions League team this season after Sergino Dest (AC Milan), Weston McKennie (Juventus), Christian Pulisic (Chelsea), Giovanni Reyna (Borussia Dortmund), James Sands and Malik Tillman (Rangers), Cameron Carter-Vickers (Celtic), Timmy Chandler (Eintracht Frankfurt), Owen Otasowie (Club Brugge) and Josh Cohen (Maccabi Haifa).