Sveum has shown a lot of faith in the youngsters who have taken over for Carlos Marmol, who was removed from the closer spot after several rough performances.
"You're open-minded to everything for the most part, but the bottom line is performance," Sveum said. "We talked about it in Spring Training -- was Dolis going to be able to handle the seventh, eighth, ninth inning with the lead, and he has. He's thrown strikes and been able to get back in counts with strikes after he's thrown a couple balls. He's proven he can do it. When guys prove they can do it, you have to use them and give them that confidence, too."
It's difficult to determine if a player has the right mentality for the job until their in those situations, Sveum said.
While the Cubs' starters have gone deep in games, Lendy Castillo and Michael Bowden have not gotten much work.
"With relievers, you try to do a matchup thing, but with guys like that, they're going to pitch in games when we're down a little bit or in the fifth inning, we might have to get the starter out of there," Sveum said of the two right-handers. "They're not the matchup guys, so to speak. They might pitch in the middle of the game when we're up by a couple because guys need days off."
Castillo, a Rule 5 Draft pick making the jump from Class A to the big leagues, has appeared in six games, while Bowden, who was claimed off waivers, has made three appearances for the Cubs.