Suero was optioned to Triple-A Syracuse on Friday, Dan Kolko of MASN Sports reports.
Suero rejoined the Nationals on July 10 and fired 2.2 scoreless innings during this stint in the majors, and now has a 3.15 ERA and 1.00 WHIP over 20 major-league innings this season. The 26-year-old will likely be one of the first options to return to Washington when it needs an additional arm as the team starts the second half with only a six-man bullpen.