Seattle Mariners power hitter Greg Halman was murdered in the early hours of Monday morning, with police confirming that his brother is in custody.
Halman, 24, was signed as a free agent by Seattle in 2004 and after a long spell in the minor leagues he was called up to the Major League team last year.
"A 24-year-old died this morning in a stabbing and we have arrested the 22-year-old brother of the victim," a Rotterdam police spokesman said.
Dutch television station NOS-TV said Halman's family had been informed.
"Greg was a part of our organization since he was 16, and we saw him grow into a passionate young man and talented baseball player," the Mariners said in a statement by chairman Howard Lincoln, President Chuck Armstrong and General Manager Jack Zduriencik.
"He had an infectious smile that would greet you in the clubhouse, and he was a tremendous teammate. Our thoughts and prayers go out to Greg's family."
MLB Commissioner Bud Selig called Halman's death tragic and painful.
"The loss of a talented 24-year-old young man like Greg, amid such tragic circumstances, is painful for all of us throughout the game," Selig said.
Halman's biggest impact may have been in Europe, said Michael Weiner, executive director of the Major League Baseball Players Association.
"Greg was passionate about the game of baseball and generously gave of himself to share his passion with others in an attempt to help grow the sport's popularity across Europe. He will be sorely missed," Weiner said.
"Greg's lasting legacy is sure to be the trail he helped blaze for European youth to follow in his footsteps."
The Dutchman helped Netherlands win the 2007 European Baseball Championship, played in the 2009 World Baseball Classic and participated in coaching clinics with youngsters in Europe as recently this month.
He is one of nine players who were born in the Netherlands to have reached the Major Leagues.
He had featured in 35 games for the Mariners last season, scoring seven runs and holding a batting average of .230.
"He seemed happy all the time and was just a fun guy to be around," Mariners infielder Adam Kennedy, now a free agent, said. "This is just devastating news."