"They've tested it and the whole nine yards. It's something they have some concern with, but it's nothing right now that they're overly concerned with at this point; but it's not normal. A lot of people have that, but that's why [he didn't pitch]."
Arrieta was a candidate to be promoted on Sunday had it not been for the injury, and the team opted to recall lefty Mike Belfiore instead. Arrieta won the team's final rotation spot in Spring Training, but was demoted after pitching to a 6.63 ERA in his first four starts. He was the Orioles Opening Day starter in 2012, going 3-9 with a 6.20 ERA in 24 games (18 starts) for Baltimore.
Norfolk used three relievers to complete the game on Sunday instead.
Brittany Ghiroli is a reporter for MLB.com. Read her blog, Britt's Bird Watch, and follow her on Twitter @britt_ghiroli. Derek Wetmore is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.