Lee also faces a potential five-game suspension, the result of him throwing a pitch over the head of D-backs catcher Chris Snyder during a March 15 game in Tucson, Ariz. Lee is appealing the suspension.
Lee recently had platelet-rich plasma therapy, a process that uses the patient's own blood to speed recovery from sports injuries.
"I am fairly new at this platelet injection stuff," Wakamatsu said. "It's pretty wild to me. There have been great results, and we're trying to be optimistic."
This is the third time Lee has had this kind of injury and the first two kept him sidelined for six weeks.
"All three of them in different spots, and we're hoping the treatment this time cuts some time off," Wakamatsu said. "We will know more after we give him a few more days off and then have him play catch again."
Lee last played catch on Tuesday and felt fine early in the session, but he began feeling discomfort again and returned to Seattle to be reexamined and it was decided to go with the platelet-rich plasma therapy.
2010 Spring Training - null
Sights & Sounds
Spring Training Info
The injury has left the Mariners' rotation up in the air.
Wakamatsu said Friday that the five-man rotation "probably" would be announced on March 31, giving each of the starters one tune-up before his first regular-season start.
Right-hander Felix Hernandez will make his final spring start that day in a Minor League game to keep him from pitching against the Rangers, whom Hernandez will face in Arlington the first weekend of the season.
Wakamatsu also said the 25-man roster probably would not be finalized until after the April 4 game against the Giants in San Francisco.
"There are so many dynamics going on with the roster," he said. "I can foresee announcing [the roster] in San Francisco."
Seattle made two roster cuts on Friday, sending catchers Eliezer Alfonzo and Guillermo Quiroz to the Minors. That leaves three receivers in camp, Rob Johnson, Adam Moore and non-roster invitee Josh Bard, and barring any setbacks with Johnson, the Mariners will begin the season with a Johnson-Moore tandem.
"Both, in my opinion, have done a great job," Wakamatsu said.