In other words, Boonie has played his last game in a Mariners uniform.
"Designating him for assignment is a real difficult thing to do," general manager Bill Bavasi said. "It's no fun for anybody involved. It's no fun for him, it's no fun for his teammates and it's no fun for me or his manager. Bret did everything on the field hard. He played his very best, gave his very best effort here and I think everybody appreciates that.
"And nobody was more tortured [than Boone] by the fact that he wasn't playing as well as he can."
Boone elected to take a few hours to digest the career-altering move before discussing it with the media.
He returned to a vacant home (his wife and four kids are in California) and gathered his thoughts before returning to Safeco Field to say goodbye to teammates and others.
It was an emotional farewell. Boone, known for his bravado, cried like a baby at times during the hour-long ordeal.
"It was tough, definitely tough," he said. "When I look at it, I think it's all for the better, really. I think it's time for me to go. It's emotional, but I'm actually excited about what the future holds."
Then, fighting back tears, he said, "It's a pretty sad day for me. You know, I have gone through a lot in this city, had a lot of great times. We have scuffled a lot the last one and a half years, but the fans have been great to me. I have had a lot of success here, played with some great guys, everyone has been awesome."
Boone has been traded three times -- once by the Mariners -- but the emotions never took over the way they did Sunday. He had to stop several times to regain his composure, and at one point when he was crying, said, "I feel like a baby."
It was difficult watching his teammates head out on a road trip without him.
"I'm really happy because I think the future is going to be good," he said. "At the same time, it's a sad deal. It's something I've never gone through."
Boone said he probably would stay in the Seattle area and work out at Safeco Field until his baseball future is determined.
"I have a lot left in me," he said. "I have some work to do, but I have a lot to offer [another team]."
Bavasi has been trying to trade Boone for more than a week, but the veteran's salary ($9.25 million) and lack of production -- .231 batting average, seven home runs and 34 RBIs -- were three strikes against a deal being made.
"We did, in fact, talk to clubs about trading him before this and did have some decent discussions," Bavasi said. "As you know, very little happens in baseball without a deadline and we decided to put a deadline on ourselves and anybody who has interest in him. Designating him for assignment does that."
It also opens up a hole at second base, and Jose Lopez was recalled from Triple-A Tacoma to fill it.
"It's as much getting Jose Lopez on the club as it is designating Bret for assignment," Bavasi said.
Lopez, 21, recently played six games for the Mariners while Boone was working on his mechanics, and went 5-for-20 with two doubles and four RBIs.
He was in the starting lineup for the series finale against the Rangers, went 1-for-3 and scored a run in the Mariners' 2-1 win. He figures to get most of the playing time the remainder of this season, and possibly for several years to come.
The Mariners also promoted outfielder Chris Snelling from Tacoma and placed reserve infielder Dave Hansen on the 15-day disabled list with tendinitis in his left elbow. Hansen is batting .194 (6-for-31) this season.
Boone is regarded as a potential Hall of Fame candidate because of the numbers he has put up over a 12-year MLB career. He went into this season with a .268 career batting average with 245 home runs and 984 RBIs.
Boone, who signed with the Mariners as a free agent prior to the 2001 season, had arguably the best season ever by a second baseman, batting .331 with 37 home runs and 141 RBIs. He finished third in the Most Valuable Player Award voting.
Though he hasn't matched those gaudy numbers since, Boone was productive in 2002 (.278, 24, 107) and '03 (.294, 35, 117), being named to the American League All-Star team in '01 and '03, and being one of two players in '03 to win both a Gold Glove (defense) and Silver Slugger (offense) that season. Alex Rodriguez was the other.
But the past two seasons have been a struggle, especially this one. He batted .202 in May and .234 in June and the team basically has underachieved for most of the season.
"If we were winning I guess there's a chance that we wouldn't do this," Bavasi said.
"Bret Boone is not the only reason that we have not played well so far," manager Mike Hargrove said. "But are we a better club today than we were yesterday? Yeah, I think so.
"I feel that it's the best thing for Bret and this ballclub, to tell you the truth," Hargrove added. "There comes a time when it's time to move on. I personally think that it was that time for Bret. Something like this is never easy. You don't like doing this to your worst enemy, much less a guy or player that you respect and like.
Bavasi said Boone was "very professional" when informed of the move Sunday morning.
"He handled it well, but he's very unhappy," the GM said. "He likes Seattle, he loves living here. He's had a lot of good times here, so yeah, it's difficult. But he handled it very, very well, very professional."
Bavasi said he would continue to attempt to trade Boone, and make other moves to improve a team that has fallen into the AL West cellar. The trade lines of communication are open, but nothing is imminent.
"Nothing that you have to carry your cell phones with you for 24 hours," Bavasi said. "We think we've got a clubhouse full of guys that believe we can get this turned around. And I think so too. However, our time is short."
Snelling, batting .363 (78-for-215) with seven home runs and 40 RBIs, becomes a spare outfielder and one of the left-handed batters on the bench.
"I can use him in the outfield to give Randy Winn a breather, occasionally," Hargrove said. "Chris gives us a little more power from the left side."