"It's a day-to-day thing," said Krivsky. "Hopefully, he can throw bullpen or something and get on pace to make a start later on. I think he feels better today. Maybe it was the plane ride, or whatever."
Milton politely declined comment on Sunday.
In other roster news, pitchers Jared Burton and Jon Coutlangus made the club following fine performances in the spring. The most notable omission from the 25-man roster was Santos.
Opening Day rosters were due to be submitted Sunday by 3 p.m. ET.
The Reds are, at this point, carrying 11 pitchers, three catchers, six infielders and four outfielders.
"Every club's trying to tweak their roster right now," Krivsky said Saturday. "They're trying to improve themselves. Most of the calls have come to me, as opposed to being initiated by me. At least, as of now."
Hermanson cut: Rather than organizing his locker for the start of the regular season, Dustin Hermanson spent Sunday afternoon saying goodbye.
The 35-year old right-hander, who had signed a Minor League deal with the Reds on March 1, was cut after posting a 7.36 ERA in eight Spring Training appearances. He allowed four earned runs in one-third of an inning on Saturday in Dayton.
Hermanson asked for and was granted his release.
"We hoped that if he didn't make our club he'd go to [Triple-A] Louisville and pitch for us, but he just had no interest in it," said Reds manager Jerry Narron. "We were all hoping that he had the same form he had a couple of years ago, but as Spring Training wound down to the end we just didn't see it."
After serving as the closer for the world champion Chicago White Sox in 2005, Hermanson spent much of last season battling back problems. Hermanson's departure and Eddie Guardado's injury leave the Reds closer situation in flux.
"It was tough to tell him he was not going to make the team," said Krivsky. "We wanted him to step up. Unfortunately the last two or three times [he pitched], we had concerns. That was a very difficult thing to do. We were all pulling for him. It would have been another nice story."
Lineup set: The Reds released their Opening Day lineup on Sunday. Ryan Freel will lead off and play center field, followed by Adam Dunn (LF), Brandon Phillips (2B), Ken Griffey Jr. (RF), Edwin Encarnacion (3B), Scott Hatteberg (1B), Alex Gonzalez (SS), David Ross (C) and Aaron Harang (P).
Injury bug: The Reds will begin the season with eight players on the disabled list.
"I'm disappointed about the guys that have gotten hurt," said Krivsky. "We've got a bloated disabled list. You never want to go into a season with that many guys hurt. It's really cut into our depth."
Among the disabled Reds is Milton, outfielder Chris Denorfia, who will undergo Tommy John surgery on his left elbow and be out six months, infielders Jerry Gil and Jeff Keppinger, outfielder Norris Hopper, starter Elizardo Ramirez and relievers Guardado and Bill Bray.
Sweet return for Lou: Cubs manager Lou Piniella managed the Reds to a World Series title in 1990. On Sunday, Piniella was at Great American Ball Park preparing his club to face his former team on Opening Day.
"[Cincinnati] has been near and dear to my heart for a long time," Piniella said. "It's a great baseball town. We'll have a nice time here on Monday."
Under Piniella, the Reds went the entire '90 season without relinquishing first-place in the National League West, then swept the heavily favored Oakland A's in the World Series.
Piniella took time to meet and greet friends and well-wishers at Great American Ball Park on Sunday.
"[Reds Hall of Fame broadcaster] Marty Brennaman is one of my favorite people in baseball," Piniella said. "He's a pistol. I love to rehash and talk baseball with him. There are lots of good people [in Cincinnati]."
Coming up: The Reds will face the Cubs on Monday in their traditional Opening Day game at Great American Ball Park. Reds right-hander Aaron Harang will oppose Cubs right-hander Carlos Zambrano. First-pitch is set for 2:10 p.m. ET.