A man who coached both Mariners outfielder Greg Halman and his younger brother in the Netherlands said the player's stabbing death on Monday is devastating to baseball fans in that country.

Eelco Jansen, who coaches the Kinheim professional team in the Dutch Major Leagues, said in a phone interview from the Netherlands that Halman, 24, was looked up to by coaches and players for his willingness to help them improve. Halman spent most of the final month of his life on a European tour with other major-league players that passed through the Netherlands, where he was mobbed for autographs and photos at baseball clinics by eager compatriots.

"For Dutch baseball, he was an icon," Jansen said.

Rotterdam Police spokeswoman Patricia Wessels told The Associated Press police were called to a home in the port city in the early hours of the morning and found Halman bleeding from a stab wound.

Officers and ambulance paramedics were unable to resuscitate Halman. Wessels said the officers arrested Halman's 22-year-old brother, Jason. He has yet to be charged with any crime but is being questioned.

Halman signed with the Mariners as a 16-year-old in 2004. The speedy 6-foot-4, 200-pounder spent seven seasons in the organization.

The Dutch-born Halman was called up from Class AAA Tacoma in May and hit a home run in his first at-bat, but was optioned back in August. In 87 at-bats in 35 games, Halman hit .230 with two home runs and six runs batted in. He appeared in nine games with the Mariners in 2010.

Jansen said Greg and Jason Halman shared an apartment in Rotterdam. Jason played catcher for Jansen's team last season, while Greg Halman was on the squad for a handful of games in 2008, but spent the past offseason with them as well during winter workouts.

"He was always open to helping make people better, and that was the same after he became a major-leaguer," Jansen said.

Jansen met up with Halman a couple of weeks ago when the major-league players' tour passed through the Netherlands.

"He hadn't changed at all," Jansen said. "Some players, when they become better than other players around them, they start to act differently. Not Gregory. He was the same as he's always been."

The two brothers were "inseparable" at times, he added, which made the events of Monday that much more difficult to fathom. Dutch news reports suggested Halman's death may have resulted after a quarrel over loud music.

"They both were more than close," Jansen said. "The slogan both of them had was 'Baseball is Life.' In my opinion, it was two guys who were almost exactly the same. Gregory took care of his little brother and Jason really looked up to him."

Baltimore Orioles pitcher Rick VandenHurk, a native of the Dutch city of Eindhoven, said he and Halman spent "24 hours a day together" on the tour before flying back to the Netherlands from Italy on Nov. 13, then headed separately to their respective homes.

"He's very well known everywhere in Holland," VandenHurk, who lives in California and has known Halman since Halman was 7 years old, said in a phone interview. "He was one of the biggest names that we have in baseball."

And Halman got the star treatment in his native country. Kids surrounded him, looking for autographs and gravitating toward the personable outfielder.

"He's very outgoing and he was great with the kids," VandenHurk said. "You could see how much they liked being around him."

Former major-league slugger Bobby Bonilla, who works for the Players' Association and was part of the tour, got to know Halman well as they rode buses to the Netherlands, the Czech Republic and Italy.

"He was trying to give back," Bonilla said. "He was doing stuff in his native country and just thrilled about it. He was very excited about the clinics he was doing over there."

Halman's closest friend in the Mariners organization was pitcher Dan Cortes. The pair met in Class AA two years ago after Cortes was traded to Seattle by the Kansas City Royals, then shared a hotel room in spring training.

They lived in the same Seattle-area apartment complex, playing video games and watching television together.

"It just ripped my heart out, man," Cortes said of hearing the news at 5:30 a.m. Monday. "It was just a blow to my gut. He was like a big brother to me. It just worked out that way. The way we joked around, helped each other out."

Mariners relief pitcher Shawn Kelley said Halman had matured greatly from the time he first entered the organization as a somewhat free-spirited, undisciplined teenager. "I didn't see him for about a year and a half, and then when I played with him again last year, he was like a completely different person," Kelley said. "He was still a lot of fun, but totally professional and dedicated to what he was doing."

Halman made an impact on Mariners both young and old this past season, his infectious personality helping lighten the clubhouse mood.

"A lot of us older guys got to know him real well, because he was one of those younger guys who was eager to listen and eager to learn," said infielder Adam Kennedy, now a free agent. "You don't always see that with young guys. ... He was just one of the guys. He seemed happy all the time and was just a fun guy to be around."

Halman was out of minor-league options, meaning he had to make the Mariners out of spring training in March or risk being put through waivers and lost to another team. He had expressed optimism to those closest to him that he thought this next step was one he was ready to make.

The Mariners removed Halman's name from their 40-man roster Monday. A statement put out jointly by president Chuck Armstrong, chairman Howard Lincoln and general manager Jack Zduriencik expressed sadness that a member of their "family" had passed.

And back in the country where Halman's exploits meant so much, the scout who first tipped the Mariners off about the teenager nearly a decade ago was still reeling. Dutch baseball coach Peter Van Dalen, who once played with Halman's father and later telephoned the Mariners about the "strong, tall and raw kid" he saw, was grappling with the scope of what had happened.

"For all of us, it's a deep shock, it's devastating," Van Dalen said from his home in the Netherlands on Monday night, adding that he'd spoken with Halman's mother earlier in the day. "He produced such good information for the kids and the baseball players here. He was a role model. Lots of kids would see ESPN and see Greg Halman's name up there and know he was one of us."

Geoff Baker: 206-464-8286 or gbaker@seattletimes.com. On Twitter @gbakermariners