General manager Jerry Dipoto said Rumbelow is still sidelined with a nerve issue in his neck, Ryan Divish of The Seattle Times reports.
Rumbelow, who was optioned to Triple-A Tacoma earlier in the month, has been unable to pitch since Feb. 24 due to the issue. This rules him out as a possible bullpen replacement for David Phelps, who was recently diagnosed with a torn UCL.