Barnes (6-3) allowed four runs -- three earned -- on three hits without retiring a batter in Sunday's 5-3 loss to the Royals.
Barnes came on in the eighth inning with Boston up 3-1, but he couldn't offer the kind of relief he's generally provided this season. He entered the game having allowed just two runs on seven hits and five walks while striking out 17 over his previous 17.1 innings. It may just be a blip, but it's a blip that comes at the trade deadline and might just spur the Red Sox to add another bullpen arm, like the Mets' Addison Reed, who can also fill in at closer when Craig Kimbrel is unavailable.