Hunter, who tossed a scoreless inning for the Baysox on Friday night, will be used out of the bullpen.
"He was 96 [on the radar gun] yesterday closing," manager Buck Showalter said of Hunter, who has appeared in three games in relief for the Orioles this season. Hunter has gone 4-8 with a 5.71 ERA in 20 starts in 2012, and he's pitched 4 1/3 innings in relief, allowing six earned runs on 10 hits and two walks, with four strikeouts.
"Tommy's pitched some big games for us starting this year," Showalter said. "Some people would think he would be a good fit in the bullpen, too."
Hunter has 13 career relief outings, going 1-1 with a 5.06 ERA. Over 21 1/3 relief innings, the 26-year-old has allowed 24 hits, 13 runs (12 earned), seven walks and three home runs. He has struck out 15.