Also left off the roster were left-handed reliever Paco Rodriguez -- who lost the second lefty role to Scott Elbert -- third-string catcher Tim Federowicz and fifth starter Roberto Hernandez.
"Our biggest fight was, 'Do we take the extra player or the extra pitcher?'" said Mattingly. "And so we never know what's going to happen or what's going to be needed, but we just felt like this roster is our best chance."
The Dodgers entered the season boasting a bullpen loaded with ninth-inning veterans, from incumbent Jansen to former World Series hero Brian Wilson, to Brandon League, Chris Perez and J.P. Howell.
And while the club pulled away to a six-game margin in winning the National League West this year, the formula for setting up Jansen turned dicey in September by poor performances from veterans Wilson and Howell, who essentially shared the eighth inning.
"I think the biggest determination for us, we're a little bit different at the end of the game than we were last year," Mattingly said. "Last year if we got to the eighth, it was one guy [Wilson] we knew we were going [with], we knew the ninth [Jansen] and pretty much knew the seventh [Howell]. So we were pretty settled at the end of the game. Now we're matching up -- multiple guys at the end of the game, so we're just using more pitchers to get where we need to go."
Mattingly said he could use Jansen for four- and even five-out saves. Jansen converted three four-out save opportunities and blew one during the season.
"This is definitely that time of the year that we would ask him for four outs," Mattingly said. "It would be tougher to go farther than that, but you know what? You're going to do what you have to do to win games at this point. These guys didn't come here this far and go, 'Oh, I'm tired, I really don't want to get five outs, Donnie.'"
But Mattingly said he would not stray radically from the matchup approach he's used recently in the eighth inning.
"We're not going to do a whole lot different than we've been doing all year," he said. "It's the playoffs and we're not all of a sudden changing everything. This is the team we've been successful with."
Regarding a second left-hander to team with Howell, Mattingly said the club felt more comfortable with Elbert's ability to end an inning and return for the next than Rodriguez. Elbert has returned healthy after three elbow operations. Rodriguez is just back from a teres major strain near his left shoulder.
Pedro Baez and Carlos Frias give the Dodgers two hard-throwing rookie right-handers, Baez for one-inning appearances in the sixth and seventh innings, Frias in a variety of roles.
"We see a number of possibilities for Carlos," Mattingly said. "If a game would go somewhere early, we can go to him. We felt like if it got really long we could go to him. His kind of stuff matches up with a lot of different guys. So trying to be a bridge to get to the back end, I think that's one of the beauties of Carlos was we felt like we could use him in a lot of different areas, and he really helped our 'pen."
Mattingly said Rodriguez, Pederson, Barney, Federowicz and Hernandez would continue to work out and travel with the club.
Scott Van Slyke