Those shirts are now available to the public for $25 at the Mariners Team Store at Safeco Field, with proceeds to benefit Dutch youth baseball programs, Carp said Tuesday.
"Maybe we can help get some more players from over there into the Major Leagues," Carp said.
Halman was stabbed to death on Nov. 21 in Rotterdam. Carp was one of four Mariners players who flew to Holland for his funeral and he's dedicated this season to his friend's memory.
Carp is currently on the disabled list recovering from a hip injury, but said he looked up in the stands Monday and saw a couple of Halman shirts already.
"It means a lot," he said. "It's like a little part of Greg is with us still."