Manager Bob Melvin says the A's want to make sure Ramirez is fully prepared and comfortable with his swing before he plays in major league games following his stint with Triple-A Sacramento. Melvin still hopes that could be on time.
Ramirez was held out of Sunday's game with the River Cats because of a wrist injury that Melvin called "a little setback."
"We want to get him close to 40 at-bats and, whether or not we get there in 10 days, I don't know," Melvin said before Wednesday's series finale against the Los Angeles Angels. "We're not locked into the 30th. We want to make sure he's productive, he's feeling good about his swing, he's getting his hits -- all of those things you want to see when, potentially, he gets here. I'm not sure on the 30th, and it's going to be a progression each and every day. We certainly hope that's the case."
Ramirez turns 40 on May 30, the day he could come back in Minnesota. His 100-game suspension for a second positive drug test was cut to 50 games after he retired for most of last year rather than serve the penalty.
If Ramirez doesn't play in the series finale against the Twins on his birthday, Oakland then heads to Kansas City for a three-game series June 1-3. His first potential home game could be June 4 against the two-time defending AL champion Texas Rangers.
The dreadlocked designated hitter is a .312 hitter with 555 homers and 1,831 RBIs. The 12-time All-Star faced a 50-game suspension for a second positive drug test.
This will be his 20th major league season. The A's signed Ramirez to a minor league contract on Feb. 20 that would be worth approximately $500,000 if he's added to the big league roster.
Ramirez ranks 14th on the career list with 555 home runs. Ramirez went 1 for 17 (.059) in five games last season for Tampa Bay.
This spring, Ramirez vowed to be ready to make a comeback with the A's.