The Red Sox are expected to designate Kahnle for assignment following Tuesday's loss to the Nationals, Chris Cotillo of MassLive.com reports.
Kahnle is poised to lose his spot on the 40-man roster after he gave up four earned runs on four hits and one walk in the eighth inning of Tuesday's contest, giving the righty an 8.00 ERA and 2.00 WHIP through nine innings at the big-league level. Alec Gamboa is expected to be recalled from Triple-A Worcester on Wednesday to claim the vacant bullpen spot.