Muller allowed four runs on six hits and two walks over 1.2 innings in Friday's Grapefruit League game against the Rays. He struck out two.
The left-hander remains in the race for a rotation spot, but Friday's outing did him no favors. Muller's 8.53 ERA and 7:3 K:BB through 6.1 spring innings would seem to put him behind Kyle Wright, Huascar Ynoa and Tucker Davidson, and he will likely begin the season with Triple-A Gwinnett.