"I've been working hard, doing everything I can to improve," the 23-year-old homegrown product said on Monday. "I'm bouncing around between third base, second base and shortstop, getting as much work in as I can, and I'll shag in the outfield during BP [batting practice].
"At the end of the day, I'm pretty exhausted. But it's a good exhaustion."
Tuiasosopo wore out a lot of opposing pitchers last spring, when he had the time of his life, batting .424 (25-for-59) with seven doubles, two home runs and 10 RBIs in 23 Cactus League games.
He was selected as the Peoria Sports Complex Spring Training Rookie of the Year and landed a spot on the Mariners' 25-man Opening Day roster.
A diamond-shaped sign located above the suites at Peoria Stadium is a permanent reminder of just how good of a camp it was for the Mariners' third-round selection in the 2004 First-Year Player Draft. He and Jeremy Reed (2006) are the only Seattle players chosen as the top rookie in camp, the other six awards going to the neighboring Padres.
With a shorter camp this spring, and stiffer competion for a roster spot, Tuiasosopo could be considered a long shot to earn a spot on the Opening Day roster this year.
But he's going to give it his best shot.
"I am trying to stay in the same mindset as last spring, and that's concentrating on what I can control," he said. "It would be huge if I can match last year."
In the meantime, he reports to work each day with a smile and an urge to get better.
"I come in here early every morning, prepare myself so that when I get into a game, I can be relaxed and have fun," he said. "That's what happened last year. When I got into a game, I was relaxed and everything just worked for me."
It worked so well that when there was talk about the 2009 season probably being the final one in Seattle for third baseman Adrian Beltre, Tui's name came up as the heir-apparent.
Drafted as a shortstop out of Woodinville (Wash.) High, Tuiasosopo was moved to the hot corner midway through the 2006 season with Class A Inland Empire (California League). After playing third most of the 2007 and '08 seasons, he became a multi-position player last season.
"I think playing a lot of positions is an advantage," manager Don Wakamatsu said, "but it could be a disadvantage for a young kid. You have to be real careful what you tell him, or more important, what he assumes -- that he's not an everyday player but more of a utility guy. That is not the case."
Wakamatsu pointed out that several big league players have changed positions during their careers and flourished because of their versatility.
The Mariners' manager called Seattle infielder Chone Figgins the "poster child" among versatile players.
Figgins was drafted and developed as a shortstop, switched to second base, played center field in the Arizona Fall League, and then left field and eventually third base for the Angels.
"He played all over the diamond and look at him today," Wakamatsu said. "You can put him anywhere and he'll do a good job. He's a premier player and epitomizes that kind of development."
Being around someone like Figgins in the Mariners' clubhouse is a good thing for Tui, who has five gloves in his locker and two more in his duffel bag.
"I have a glove for every position except catcher," he said. "I was going to order one during the offseason, but didn't get around to it."
It's anyone's guess which position -- or positions -- gets Tuiasosopo to the big leagues for good. He has had a couple of brief stints the past two seasons, batting .182 (12-for-66) with one home run and four RBIs.
"Tui's greatest asset is his work ethic," Wakamatsu said. "The only thing he needs to do is get more and more at-bats and shorten his swing a little bit.
"Last year was a tough year for him because of the injury. He lost some time and he's searching a little, trying to adjust to what we are talking about."
Wakamatsu was referring to Tuiasosopo's right elbow, which apparently was injured in Spring Training. Tui ended up having surgery to remove bone chips and bone spurs and was sidelined from late April to mid-July.
"I had been doing extra work at second base after being sent to the Minor League camp," Tuiasosopo recalled. "I was throwing at different angles and it started getting a little sore."
He played through the pain and was invited to join the team for the trip to Las Vegas for the final two Spring Training games.
He played one of them and remained with the Mariners for the first week of the regular season. But he never played in a game and was sent back to Triple-A Tacoma on April 16.
The soreness in his elbow worsened and Tuiasosopo finally had his first-ever surgery, returning in time to help the Rainiers finish strong and reach the Pacific Coast League playoffs.
When Beltre departed via free agency, the Mariners signed Figgins, presumably to become the new third baseman, although that has yet to be determined.
"I knew they were going to do whatever they needed to do to make this team better," Tui said. "I was excited when we got Figgins and everyone else. It's amazing what Jack [GM Jack Zduriencik] has done with this team."
"I am just trying to put myself in position where I hold my own and be a part of everything that's happening with this team," he said. "I can learn from everybody. Jack Wilson and I have talked about defense, and I have talked to Milton [Bradley] about hitting.
"I am picking their brains, asking what they did when they first made it to the big leagues. This is my sixth Spring Training and have grown a lot in those six years, but I' m still learning things.
"I want to make sure I am doing what I need to do, and whatever happens, happens."