Gausman, 23, will miss at least one start and, if it doesn't improve, he could end up on the minor league disabled list. He is 0-1 with a 2.53 ERA in five starts for the Tides.
In his last game April 26, Gausman was limited to just 75 pitches and 4 2/3 scoreless innings. But Showalter said that was because the club was hoping to keep his workload down so there wouldn't be an innings limitation on him at the end of this season in the major leagues.
The injury, Showalter said, seemed to crop up Thursday.
** After the second game Thursday, the Orioles announced that they had optioned reliever Evan Meek to Norfolk. They are expected to call up a reliever Friday to help fortify a bullpen that threw nine innings in Thursday's doubleheader.
The most likely candidate is right-hander Preston Guilmet, who is 2-0 with a 1.80 ERA and three saves in eight games with the Tides. The 26-year-old Guilmet was acquired in April from the Cleveland Indians in a trade for minor league infielder Torsten Boss.
Guilmet was held out of Thursday's game in Norfolk and is on the 40-man roster. Guilmet pitched in four games for the Indians last year, allowing six earned runs in 5 1/3 innings (10.13 ERA).
Other possibilities on the 40-man roster include right-hander Suk-min Yoon, who is 0-3 with a 5.24 ERA at Norfolk, but has pitched better recently; and left-hander Tim Berry, who is 1-1 with a 3.86 ERA in five starts at Double-A Bowie.
Brad Brach would have been a possibility, but he pitched Thursday for the Tides. Showalter said the Orioles also would consider pitchers who were not on the 40-man roster.
Meek was 0-1 with a 6.94 ERA in 12 appearances with the Orioles. He allowed one run, one hit and two walks in Thursday's nightcap.