Nomo announced his retirement on Thursday, nearly three months after he was dropped from the Royals' roster.
"Just being around him made us all a little bit better, honestly, just because of the way he goes about his business and the professionalism that he shows to his craft," Hillman said.
Nomo, given a tryout as a non-roster pitcher in Spring Training, suffered a groin injury late in camp and was not on the Opening Day roster. But he was placed on the Royals' roster on April 5.
"The way things fell, I really believed that he was going to be successful for us in the bullpen," Hillman said.
Nomo pitched in three games, but had an 18.69 ERA in 4 2/3 innings. His last appearance was on April 17 at Oakland. He gave up a three-run homer to Bobby Crosby, but struck out the last batter he faced, Travis Buck. When the Royals needed a starting pitcher to replace injured John Bale, they called up Luke Hochevar and designated Nomo for assignment.
A Japanese trailblazer when he left the Kinetsu Buffaloes, Nomo joined the Los Angeles Dodgers in 1995. He and his agent, Don Nomura, were harshly criticized at the time for leaving Japan.
"He had to overcome a lot of things, emotionally. That shows a lot of mental strength to me, going from being considered a traitor to becoming a hero when he won the Rookie of the Year," Hillman said.
The first Major Leaguer from Japan in 20 years, Nomo was a sensation with the Dodgers, inciting "Nomo-Mania" both in the U.S. and his home country. He was noted for his deceptive "Tornado" delivery and his sharp-dropping forkball.
He started that year's All-Star Game, became the National League's top rookie and eventually won 123 games, including two no-hitters, one for the Dodgers and one for the Boston Red Sox.
"Nomo had a dream," Hillman said, "and he followed his dream and his vision to come over here. And he had the confidence to do what he did. He was a great pitcher."
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.