Stahl was the Union's selection in the second round of the 2010 MLS SuperDraft. Taken 17th overall, the Finnish player failed in impress head coach Piotr Nowak. USMNT up-and-coming defender Tim Ream was taken by the New York Red Bulls only a pick later. In his only MLS game, Stahl received a red card in the first 19 minutes of the match. He did not make another appearance for the team in anything but the US Open Cup.
Brought in to take over at right back, Arrieta never cemented his starting role. When Nowak replaced Arrieta with Michael Orozco-Fiscal midseason, it was the end for the former Puerto Rico Islanders star. The addition of Sheanon Williams clinched the departure of Arrieta, who looked distant during the preseason, prior to his release.
Stahl and Arrieta join former teammate Eduardo Coudet, and former Union trialist Aaron Wheeler, in Ft. Lauderdale. Coudet was let go, like Arrieta, during the preseason after being seen as a surplus to Nowak's 'requirements.' Wheeler spent time training with the team during the preseason but ended up with the Strikers.