First-base coach Todd Steverson, who managed Cunningham at Sacramento last year, told him he'd been optioned back to the River Cats while Cunningham was already in the process of packing his things.
"I guess they couldn't find me," Cunningham said with a shrug.
Tomko, 36, was signed by the Yankees to a Minor League contract on Feb. 20 and began the season at Triple-A Scranton-Wilkes Barre. He went 1-0 with four saves and a 0.64 ERA in 10 relief appearances before being promoted to New York on May 9.
A 13-year veteran who has pitched for nine big league teams (including Monday's game for the A's), was 1-2 with a 5.23 ERA in 15 relief appearances with the Yankees upon being designated for assignment on July 21. He was released July 29 and signed a Minor League contract with the A's on Aug 5.
Assigned to Sacramento for the purpose of getting stretched out for a possible starting role in Oakland, Tomko did not have a decision and posted a 7.94 ERA in three games (two starts) for the River Cats.
A's manager Bob Geren said the decision to send out a position player was made because Tomko isn't quite stretched out far enough to afford the luxury of a seven-man bullpen.
"For the time being," said the skipper, "I need the extra reliever."
Cunningham was recalled from Sacramento on Aug. 8 for his third stint with the A's this year, and he was 1-for-7 (.143) in seven games. He is batting .151 with a home run and six RBIs in 23 games overall with Oakland this season.
"I did see some improvement in his throwing; I like that," Geren said of Cunningham, who likely will be brought back up, at the latest, when the rosters expand on Sept. 1. "He didn't get a ton of at-bats, [but] he's a talented young player."
Cunningham, 23, is batting .300 with nine home runs, 42 RBIs, a .369 on-base percentage and a .485 slugging percentage in 65 games with Sacramento this season.