Splittorff, 64, spent his entire 15-year career with the Royals, from 1970-84. A big left-hander, he holds the Royals' career record for victories (166), starts (392) and innings pitched (2,554 2/3). In 1973, he became the club's first 20-game winner.
He has worked in broadcasting since retiring as a player and was in his 24th season as a television analyst for FOX Sports Kansas City.
Splittorff also worked as a basketball announcer and missed some assignments during the 2008-09 season because of medical problems.
Royals fans became aware of Splittorff's difficulties during the Opening Day telecast from Chicago on April 8, 2009. He teamed with Ryan Lefebvre to do the game but had problems with his voice and returned home.
"From the very beginning, he didn't want anybody to feel sorry for him because he was determined he was going to fight this and he's going to continue to fight this," Lefebvre said.
Splittorff worked determinedly to recover and has worked intermittently on Royals and Big 12 basketball telecasts ever since. He appeared in pre- and postgame broadcasts this year, and also worked in the booth during a series in Texas. He was scheduled to work last week's series in New York but that was canceled.
"He worked at it, he did speech therapy, and I really thought there was a point when he was sounding more like himself," Lefebvre said. "We really didn't know the extent of it and we respected the fact that he didn't want to talk about it, not to mention that if somebody asked him about it he'd say, 'I'm doing fine.' "
Former second baseman Frank White, a teammate of Splittorff, took over the TV analysis in 2009 and has continued in that capacity ever since.
Club officials withheld comment, citing the Splittorff family's request for privacy, and stated that there would be no further comment on his condition.
The news of the popular Splittorff's hospitalization hit his associates hard.
His former TV partner and current radio voice Bob Davis became close friends with Splittorff and respected how well he performed in the broadcast booth.
"He really worked at it," Davis said. "He took it real seriously. And he did basketball, too, because he had the background as a college basketball player. A fun guy, but very private."
Splittorff was a two-sport star in baseball and basketball at Morningside College in Iowa. But veteran Royals scout Art Stewart remembered watching Splittorff pitch even before that, in both high school and with the Arlington Heights (Ill.) American Legion team that reached the 1965 Legion World Series in Aberdeen, S.D.
"He didn't throw that hard, but he was one of the smartest young pitchers I ever saw. [He had] moxie, and even as a young pitcher he retained what he knew on a hitter," Stewart said. "None of us were smart enough to draft him because he didn't throw hard. So he went to college and we drafted him. Then I saw him after we signed him and he was throwing harder, his fastball was a little better. He always had the good breaking ball, the good changeup."
Splittorff carried that over in the Major Leagues, surfacing with the Royals in 1970. As a rookie in '71, he showed his promise with a 2.68 ERA and an 8-9 record. In '73, he went 20-11, and he came close to that level in '78, when he went 19-13.
"I remember how competitive he was," said Denny Matthews, the Royals' long-time radio broadcaster. "[His] focus was excellent, concentration was good, very competitive. He got the most out of his physical gifts and he worked hard -- I think he just out-worked a lot of guys to have the career that he did."
In 15 seasons, Splittorff had a 166-143 record and 3.81 ERA in 429 regular season games. He was in four postseasons with the Royals, 1976-78 and '80, reaching the World Series in the latter year. His postseason mark was 2-0 with a 2.79 ERA.
The Royals family was united in wishing Splittorff a complete recovery.
"If mental toughness and competitiveness get you through, then he'd be a prime candidate to get through it," Matthews said.
Lefebrve had this to say to a TV reporter: "We've all been asked quite a bit about him today, and all of us, I'm sure, are very careful in what we say, because if he's watching this somewhere he's thinking, 'Why are you spending all this time talking about me? You've got a game to do.'"
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.