As of Sunday, the Mariners still had not announced how many players would be promoted, although Wakamatsu said right-handed pitcher Brandon Morrow would be among those spending at least some of the final month of the regular season with the team.
"We're still discussing that right now," Wakamatsu said. "Obviously, we'd have to take somebody out of the rotation and that's a little tough right now when guys are pitching well. We definitely will see him in September. We just don't know when yet."
Morrow, who started the season as the Mariners' closer but faltered and was re-assigned to Triple-A Tacoma to become a starter, has performed well recently and the Rainiers are still mathematically alive in the Pacific Coast League.
The PCL regular season ends on Sunday and Morrow probably would remain with the Tacoma club until its season ends.
Left-hander Garrett Olson could be one of few Minor Leaguers promoted to the Mariners for the stretch run. The Seattle bullpen has logged a lot of innings this season and Olson could ease some of the burden.
With first baseman Russell Branyan on the 15-day disabled list with a herniated disk, his status for the remainder of the season is uncertain, which could precipitate a return to the big leagues for first baseman Mike Carp.
"I think [the remainder of the season] will depend on how my body responds to the rest and the treatments," Branyan said. "A week into this thing, I may be feeling 100 percent better and as long as the symptoms changed and I'm pain free, I can start getting back onto the field. I don't want to re-aggravate it a week and a half from now. I want to make sure it's 100 percent first."
Carp is batting .274 with 15 home runs and 64 RBIs for the Rainiers. Veteran catcher Jamie Burke, who has split his time this season between Tacoma and Seattle, would be another promotion candidate -- giving the Mariners three catchers for the stretch run.
Another possibility is introducing catcher Adam Moore to the big leagues. He has had a solid season at Tacoma, batting .291 with nine home runs.
With a week of the Minor League season remaining, Mariners management is adamant against releasing the names of the players even being considered for a promotion because club officials believe it could affect the play of those not on the list.