Leake spent the entire season with the team as the fifth starter, and Ondrusek was with the club for all but 10 days that were spent in Triple-A.
"You hate to have guys that have been with you over a long period of time [not make the team], but you have to take your emotions out to decide and go with who you think is the best pick at the time," Baker said.
Hoover, a rookie acquired from the Braves in the Juan Francisco trade on April 1, posted a 2.05 ERA in 28 games over two big league stints with the Reds this season. Simon, a waiver-wire pickup from the Orioles after Spring Training, had a 2.66 ERA over his 36 games this season.
Ondrusek posted a 3.46 ERA in 63 appearances this season but struggled down the stretch. He had a 5.02 ERA over his final 16 games, with nine walks and 18 hits over 14 1/3 innings. But he was given a couple of appearances in the past week to try and help his cause.
"That was kind of by design at the end to try and make up our mind," Baker said. "That was one of the luxuries of having a big lead and clinching early. You can sort of see that.
"It just boiled down to who was going the best at the time. It's always a tough pick, a tough call."