The Orioles today announced that they have placed right-hander Jason Hammel on the 15-day disabled list, retroactive to July 14, with a right knee injury and recalled right-hander from Triple-A Norfolk.
In 18 starts for the Orioles, Hammel is 8-6 with a 3.54 ERA (109.1IP, 43ER).
Johnson, 24, was 3-6 with a 3.11 ERA (66.2IP, 23ER) in 15 games (20 starts) for the Tides. He was acquired by the Orioles with infielder Josh Bell on July 30, 2009 in exchange for left-hander George Sherrill.
Johnson was on the Orioles' roster July 2-3 in Seattle, but did not appear in a game. He will be making his major league debut.
Steve, and his father, Dave, who pitched for the Orioles from 1989-91, will become the sixth father-son duo to play for the Orioles, joining Bob and Terry Kennedy, Don and Damon Buford, John O'Donoghue Sr. and John O'Donoghue Jr., Dave and Derrick May and Tim Raines Sr. and Tim Raines Jr.
Johnson, a product of St. Paul's School in Baltimore, will wear uniform number 52.