BALTIMORE — The A’s have recalled switch-pitcher Pat Venditte and right-hander Dan Otero from Triple-A Nashville to add bullpen depth ahead of Saturday’s game against the Baltimore Orioles.

In corresponding moves, Oakland optioned right-hander Aaron Brooks to Nashville and designated Brad Mills, Friday night’s starter, for assignment.

The A’s bullpen worked seven innings in Friday’s 8-6, 13-inning loss to the Orioles.

Venditte, the 30-year-old rookie who generally pitches with whatever arm gives him a platoon advantage against the hitter, allowed no earned runs in four games (5﻿2/3 innings) earlier this season before a right shoulder strain sent him to the disabled list.

Since returning from injury, Venditte has made nine appearances in the minors, allowing no runs in five of his last six appearances.

“It’s a nice little toy to have in your chest and nobody else has one,” manager Bob Melvin said. “But the fact that he’s performed well is what makes you feel good about bringing him in.”

Mills leaves the A’s after allowing three runs over five innings Friday in his only big league outing of 2015, a spot start forced by Sonny Gray missing his start Thursday in Toronto because of back spasms.

Gray threw 25 pitches in a bullpen session before Saturday’s game, and Melvin said he will wait to see how Gray feels Sunday before determing if he will pitch Monday in Baltimore or Tuesday against the Dodgers at the Coliseum

Brooks (1-1, 6.20) was originally slotted to start Monday’s game, but was summoned to work the 13th Friday as lefty Drew Pomeranz exited with elbow tightness. Manny Machado belted Brooks’ second pitch out of the park to give the Orioles the victory.

Otero (2-4, 5.79) has pitched in 29 games for the A’s this season.