Around the horn: Closer Zach Britton (left forearm strain) made his second rehabilitation appearance Thursday at Low-Delmarva. Britton pitched another scoreless inning, allowing one hit while striking out two and walking none. He threw 16 pitches, 11 for strikes. ... Russell said the challenge of standing in for a day is to make sure the bullpen remains in order for the following day, which is a continuing challenge for the Orioles. … Reliever Darren O’Day (shoulder) is on track to be activated from the disabled list Friday, before the series opener at the Tampa Bay Rays, Russell said. … The Orioles announced Thursday that they signed second-round draft pick Adam Hall, a shortstop, and fifth-round pick Lamar Sparks, a center fielder. ... Outfielder Austin Hays, the Orioles' 2016 third-round pick, was promoted from High-A Frederick to Double-A Bowie on Thursday. Hays, 21, batted .328/.364/.592 with 15 doubles, 16 homers and 41 RBIs in 64 games with the Keys.