Thanks to some special roster rules MLS teams can use players from their USL affiliate to help them in the US Open Cup for up to 4 matches each. Seattle Sounders FC used these special short-term loans heavily in the 4th and 5th round of the 2017 Open Cup and it is likely they will do so again for their 2018 4th round matchup against unaffiliated USL side Sacramento Republic FC. The other US Open Cup rule to keep in mind is that only 5 players in the game day 18 can be international players, which will limit the Seattle Sounders FC 2 players they can use.
Sounders have promising options at S2 for US Open Cup reinforcements
