Diaz (1-2) took the loss Friday as the Mets fell 1-0 to the Nationals, allowing one run on two hits and a walk without recording an out.
Entering a scoreless game in the bottom of the ninth inning, Diaz walked Juan Soto to lead off the frame, then served up singles to Ryan Zimmerman and Yan Gomes to hand the Nats a walkoff win. The right-hander had a 0.77 ERA over his prior 12 appearances heading into Friday but non-save situations can bring out the worst in a closer, and Diaz's job is in no jeopardy.