The Triple-A Norfolk Tides face the Indianapolis Indians on the road, while the Double-A Bowie Baysox travel to play the New Britain Rock Cats.
The Single-A Frederick Keys host the Potomac Nationals for a doubleheader at Harry Grove Stadium, and the Single-A Delmarva Shorebirds and Hagerstown Suns will meet at Municipal Stadium.
The pitching carousel is starting to spin in the Orioles' minor league system.
Jake Arrieta will pitch for the Tides tonight after being promoted from Bowie, while right-hander Tim Bascom moves up to the Baysox from Frederick to make tonight's start.
There were a few other roster moves in Norfolk today.
Right-hander David Hernandez rejoins the Tides, and left-hander Bobby Livingston was sent back to the Baysox. Also, Norfolk infielder Justin Turner was placed on the disabled list, retroactive to June 9, with a sprained right wrist.
Left-handed pitcher Troy Patton hasn't officially been added to the Tides' roster at this point, but that move will come within the next few days.
at Indianapolis Indians (7:15 p.m.)
Norfolk: Jake Arrieta (6-3, 2.59 ERA with Bowie)
Indianapolis: Eric Hacker (1-1, 4.66 ERA)
at New Britain Rock Cats (6:35 p.m.)
Bowie: Tim Bascom (4-5, 3.40 ERA with Frederick)
New Britain: Matt Fox (5-2, 2.81 ERA)
* The Baysox are in fourth place in the Eastern League Southern Division with a 30-29 record. Bowie trails the division-leading Akron Aeros (38-20) by 8 1/2 games. New Britain (32-27) is in second place in the Northern Division. The Rock Cats are 1 1/2 games behind the division-leading Connecticut Defenders (34-26).
Doubleheader vs. Potomac Nationals (5 p.m.)
Game 1: Probable pitchers
Frederick: Pedro Beato (4-4, 4.35 ERA)
Potomac: Will Atwood (1-5, 6.39 ERA)
Game 2: Probable pitchers
Frederick: Chris Salberg (1-3, 7.39 ERA)
* The Keys (27-32) dropped the first two games of their series against the Lynchburg Hillcats (38-20) before last night's matchup was canceled due to rain. Frederick remains in last place in the Carolina League Northern Division, trailing the Hillcats by 11 1/2 games. Potomac (32-25) is tied for second place in the division, and the Nationals are 5 1/2 games behind Lynchburg.
at Hagerstown Suns (7:05 p.m.)
Delmarva: Nathan Moreau (1-1, 5.91 ERA)
Hagerstown: Marcos Frias (4-1, 2.31 ERA)
* The Shorebirds (31-24) are in second place in the South Atlantic League Northern Division, and they are 1 1/2 games behind the first-place Lakewood BlueClaws (34-24). Hagerstown is in sixth place in the division with a 26-29 record. The Suns are 6 1/2 games behind Lakewood.