The two are fast friends back in Japan, working out together over the offseason and having played together on their national World Baseball Classic championship team in 2009. Kawasaki, in fact, said he'd only signed with the Mariners and accepted a Minor League deal just to have the chance to play with Ichiro.
But it's taken all of two days in Spring Training to understand the two are polar opposites in their personal approaches, with Kawasaki wasting no time letting his extroverted self be seen and heard throughout camp.
The 30-year-old infielder is a chatterbox, talking aloud in a constant stream of Japanese, even when no one around him understands a word. When the Mariners are taking infield grounders, he shouts out in Japanese before every ball hit to him. In the clubhouse, he's quickly created a bond with players who raise their eyebrows in amusement and can't help but get caught up in his enthusiasm.
"The energy," said teammate Brendan Ryan, a non-stop sort himself, "is kind of refreshing."
In Japan, it's common for players to yell out during practices, though even there he was regarded as one of the more energetic leaders. But the interesting thing is that, even in a new culture and environment, Kawasaki had the confidence to come in and stick with that style rather than try to fit in with the quieter Major League approach.
"I'm just being myself," Kawasaki said Sunday through interpreter Antony Suzuki. "I'm just trying to communicate in Japanese, because I don't know the language. Now, if you were to ask me how much they understand, I couldn't tell you.
"I don't know how much we've communicated, but that's just my style, and that's how I've been in the past, and that's how I'd like to stay, because that's what got me here."
Kawasaki surprised many in Japan by giving up a likely $2-3 million deal with the Fukuoka Softbank Hawks for a contract that will pay about a third of that if he makes the Mariners, which comes with no guarantee given his acceptance of a Minor League pact.
But this is Kawasaki's American dream, his shot at taking his game to a new continent, with the chance to play with his longtime idol Ichiro.
"I'm very happy to be here," he said. "I'm enjoying every day."
His new teammates are enjoying his enjoyment, as it were. Sometimes it's good to be reminded of the fun side of baseball, a reminder that comes with every unintelligible shout from Kawasaki during drills.
"He's obviously passionate about the game. That comes across first," said Ryan, who has been working alongside Kawasaki at shortstop. "It's nice to be surrounded by those kinds of people. I feel like I'm one of those kinds of guys, and I think it's rubbing off on other guys. I think right now we're all kind of entertained by it, but we'll see. It's been fun so far."
As for what exactly Kawasaki is yelling out?
"I don't know if they're like softball chants or, 'We want a hot dog, we want a Coke' stuff," Ryan laughed. "It doesn't really matter. It's kind of more fun not knowing, I think."
Japanese reporters covering Kawasaki, Ichiro and fellow newcomer Hisashi Iwakuma this spring say Kawasaki isn't really yelling sentences, but just saying 'Hey" or "Let's go" type phrases before the ball comes his way.
On Saturday, he fired a ball over to first baseman Justin Smoak and then yelled out, "Yay, Smoaky," so he's clearly picking things up quickly.
As for the Mariners and their Japanese comprehension? Not so much.
"I don't understand anything he's saying, but sometimes I act like I do," Smoak said with a grin. "But it's good to be around him. He's got a lot of energy. And so far, it's been pretty entertaining."
Kawasaki displays a smooth glove, and clearly is in the mix to land a utility infield job. With Ryan still limited in his throwing by a shoulder problem suffered at the end of last season, Kawasaki's potential role could become even more critical.
The biggest question seems to be whether he can hit Major League pitching, but the 5-foot-10, 165-pounder batted .294 in 10 years in Japan and appears to be a capable line-drive hitter in batting practice.
"He's a baseball player," said Mariners manager Eric Wedge. "Obviously he's had a tremendous career in Japan, and he's made the choice to come over here and compete and work hard to make the club. We're going to give him every opportunity to do that, as we will with so many others."
Kawasaki clearly has caught Wedge's attention with his energetic approach. Much more will be learned when games get under way, but for now, he's taking on the challenge of a new environment with a head-on approach that suggests he'll be a quick study there as well.
"I don't see too much difference," Kawasaki said of his first week in a Major League camp. "It's still the same game. It's still baseball. I can say we have a lot of players with speed and power here, and that's very attractive."
Ryan, one of the premier defensive shortstops in the Majors, certainly appreciates what he's seen so far as well. He has constantly praised Kawasaki's efforts in the field, offered tips on dealing with the dry playing surfaces in Arizona and encouraged the newcomer's enthusiastic approach.
"You see confidence. You see a guy with experience. You just see a certain cleanliness with good infielders," Ryan said. "They may not always be in the right position, but you still see the ball coming out of the glove in the right place and the transfer and the athleticism, also. He looks like he'd be comfortable anywhere."