But apparently the move indeed was close to happening.
"We have long viewed Brandon as a starter. ... At the start of this season, we thought his greatest value to the team in 2008 was in the bullpen," interim general manager Lee Pelekoudas said in a press release.
"As our season progressed and it became obvious we were not going to reach the goals we had entering this year, we began internal discussions on the best time to convert Brandon back to a starting role. We believe that giving him time to stretch out in Tacoma and then, hopefully, make some starts for the big league club before spending the 2008 offseason preparing to come to camp as a starting pitcher for 2009 is the best route for his development."
Morrow, who has a 1.47 ERA this season, has never been shy about stating his desire to be a starting pitcher in the Major Leagues.
"Starting -- getting a quality start -- is more important than getting a couple outs in the seventh, eighth inning," Morrow said in May.
A starter in college at the University of California-Berkeley, the hard-throwing right-hander now gets his opportunity to fulfill his goal in Tacoma. He will start there on Wednesday with a 35-pitch limit, and he will work on a five-day rotation after that.
"When you talk to Brandon, you don't get a lot of response. He's just basically saying, 'OK.' If you put the question to him, 'What do you want to do?' He'll say, 'Start,'" Riggleman said. "I just hope it works out, and we get him back here and he's an effective starter for us."
How Morrow responds to the extended pitch count and throwing between his starts will determine exactly when he comes back to the Mariners. He has only reached the two-inning mark once this season -- the only time he threw more than 1 1/3 innings -- and he never threw more than 30 pitches. Riggleman gave a rough estimate of four to six starts that Morrow might get with the Mariners should everything go according to plan.
The extended work also might change Morrow's pitching style a bit.
"His breaking ball and his changeup are, at times, very good. The test is going to be to carry those pitches into the second time through the lineup, third time through the lineup at some point," Riggleman added. "And really be able to pitch with less than a 98 mph fastball. You're really not going to plan on starting a game and still throwing as hard as he throws that long through the game -- that's going to put a lot of stress on you."
The most recent high-profile example of an ace reliever becoming a starter is the Yankees' Joba Chamberlain, who has excelled in the role but left his last start with stiffness in his right shoulder and will see well-known orthopedic surgeon James Andrews on Wednesday.
Riggleman pointed out that Morrow's health could rest on his own honesty.
"Brandon's going to have to be straight forward with the training staff and the pitching coach to let them know that, 'I feel great' or 'I don't,'" Riggleman said. "And I'm sure that's what Chamberlain did. He expressed that he's got a little discomfort."
Riggleman also said J.J. Putz has told him he feels strong, which assures the manager that Putz can step back into his normal closer role. Morrow filled in at that spot while Putz was injured.
And with Wladimir Balentien also coming up on the same day as Morrow's transition, the Mariners are making bigger moves with eyes toward next season.
"We're entering a mode right here of trying to win ballgames, but also trying to find out some things about how much guys can do and what roles they can be successful in," Riggleman said.