Roberts, currently on the disabled list, underwent an MRA yesterday. The procedure is similar to an MRI, except dye is injected into the injured area.
Roberts will seek a second opinion, according to Showalter.
More details are coming on "O's Xtra" on MASN2 HD, beginning at 9:30 p.m.
Also, left-hander Brian Matusz, making his first start with Triple-A Norfolk, is working on a two-hit shutout through six innings in Charlotte. He's walked one and struck out three.
Matusz has thrown 56 of his 82 pitches for strikes.
Steve Tolleson isn't in Norfolk's lineup tonight. He's expected to be recalled tomorrow and join the Orioles in Anaheim.
Update: Matusz has allowed three hits over eight scoreless innings, with one walk and four strikeouts. He's thrown 99 pitches, 71 for strikes.
Update II: If Matusz was looking for a confidence boost, he found it in Charlotte. He tossed a four-hit shutout, walking one and striking out four. He threw 114 pitches, 81 for strikes.
Now it's Zach Britton's turn tomorrow night.