"I'm a believer that closers come from a lot of different places," Epstein said. "You find a guy with some swing-and-miss stuff and some courage and effectiveness earlier in the game, you should try him in the ninth inning because he has enough balls and enough stuff that he can handle the ninth inning."
Gregg will be a free agent, and could return next year. Other options include Pedro Strop, acquired from the Orioles in the Scott Feldman deal, and possibly Justin Grimm.
"The bigger story for me is that we started out the year with a bullpen that didn't perform well, and that's our fault," Epstein said, pointing the finger at the front office. "I think over the course of the year, it really steadily improved. The pitchers deserve a lot of credit."
• Josh Vitters and Brett Jackson were on the Cubs' big league roster at this time last year, but this was a difficult season for the first-round picks. Epstein said Vitters, who was the No. 1 pick in 2007, will be converted to an outfielder this offseason.
"We're converting him to left field," Epstein said. "He's going to come to Spring Training ready to re-establish himself and force himself into the mix as one of our right-handed hitting outfielders."
Jackson, the Cubs' first-round pick in 2009, battled injuries this season and ended on Double-A Tennessee's roster. Epstein said Jackson may follow the same program as Vitters this offseason.
• Shortstop Javier Baez, the Cubs' No. 1 pick in 2011, was named the Minor League Player of the Year after an impressive season. Fans want to know when Baez, rated the organization's No. 1 prospect by MLB.com, will be in the big leagues.
"He's got all the ability that he needs to play Major League shortstop, not that he's not still developing," Epstein said. "We have a shortstop now [in Castro]. If we're fortunate to get to that point in time where Baez is pounding on that door and Castro is healthy, then we will look to move Baez around so he can perform at other positions. I think he has a lot going for him, that he can do that. For a young kid, he has tremendous baseball instincts."
Epstein also said outfielder Albert Almora, the Cubs' 2012 first-round pick who was sidelined with a groin injury, was healthy and preparing for the Arizona Fall League. Cuban outfielder Jorge Soler, bothered by a stress fracture of his tibia, was also doing baseball activities and preparing for the AFL.