In the postseason, in the biggest games, teams start their aces whenever they can. For the Dodgers, that's clearly Clayton Kershaw, who is going to get the ball in Friday's Game 1 of the National League Championship Series. For the Brewers, it's not quite so clear. As they've made clear all season and especially in the NL Division Series, their ace might not be one man. It might be the entire bullpen, deployed strategically as needed to put each pitcher in position to maximize their talents. 
That's not to say they won't kick off games with a traditional starting pitcher, because they often will. But we also saw them start rookie reliever Brandon Woodruff as the "initial out getter" in the first game of the NLDS, and we saw them start reliever Dan Jennings for all of three pitches to retire Matt Carpenter on Sept. 24.
Now, they have a different challenge. The Rockies' offense they faced in the NLDS was a weak group, one with several obvious flaws that managed to score in only one inning of the three games. The Dodgers, meanwhile, are a more formidable opponent, having led the National League in runs scored, home runs, slugging percentage and walk rate, and coming in second in hard-hit rate -- to Milwaukee.
It helps, also, that Dave Roberts and his Dodgers have the depth and flexibility to counter some of Craig Counsell's bullpen moves. Los Angeles is running clear platoons at first base, left field and right field, with an argument for a fourth at second, though Enrique Hernandez's production against righties and the struggles of James Dozier have muted that conversation for the moment.

Just look at how differently the Dodgers' lineup functions against lefties or righties, at those three spots.
Player Page for Max Muncy, Joc Pederson and Yasiel Puig
Against LHP .218/.292/.408 90 wRC+  (100 is league-average)
Against RHP .273/.365/.573 153 wRC+
Yes, Puig is a righty who starts against righties, as he's now two full seasons into performing better against them than lefties. While Muncy has been strong against all pitchers, Pederson is unplayable against lefties, hitting .170/.211/.302. Against righties, this trio has been about as productive as Alex Bregman.
Matt Kemp, Chris Taylor and David Freese
Against LHP: .271/.341/.473 122 wRC+
Against RHP: .279/.339/.457 117 wRC+
This is the trio that enters against lefties, though the difference here really isn't that stark. It's mostly about covering for the weaknesses against lefties that the first group showed above. There's so much depth here.
And that's the question, really. What Dodgers lineup should the Brewers want to see, and when? Roberts' lineup will be written in reaction to Counsell's pitcher, so the Brewers have some control here.
There's no shortage of ways they could play this. Let's take a crack at it.
Game 1: Start Jhoulys Chacin
Chacin isn't your traditional "ace," but he's been effective for Milwaukee, and part of the reason they went with Woodruff in Game 1 of the NLDS was because Chacin had pitched Game 163 just three days earlier. Thanks to a slider that is arguably one of the absolute best pitches in baseball, Chacin has actually been brutal on righty hitters, allowing a line of only .171/.244/.284 against.
Of the 95 starters to face 300 righty hitters, his weighted on-base average of .234 is third best, in the middle of some impressive names.
.205 -- Jacob deGrom
.223 -- Miles Mikolas
.234 -- Chacin
.239 -- Max Scherzer
.245 -- Chris Sale / Zack Wheeler
.250 -- Corey Kluber 
If Chacin being on the mound leads to the lefty Dodgers lineup, that could work for Milwaukee. Against righty sliders, Muncy hit .196, though with a .478 slugging. Pederson hit just .133 with a .333 slugging. (Counterpoint: Puig smashed righty sliders, with a .620 slugging percentage.)
Let him go through the order twice (.197/.285/.338 this year), then turn it over to the bullpen before he goes the third time or more (.278/.349/.432).

Game 2: Bullpen game
Let's acknowledge that Wade Miley has been fine, and rookie Freddy Peralta is fine, and so are Chase Anderson and Giovany Gonzalez and Zach Davies and Junior Guerra, but none are as good as a steady stream of high-quality relievers. Due to the travel day between Games 2 and 3, and assuming nothing disastrous happened to a well-rested group in Game 1, this is a good time to break out the relievers without burning them out for the rest of the series.
"There's three or four guys that get a majority of the attention, but if you look at the way Corbin Burnes is throwing the ball right now, the way Brandon Woodruff is throwing the ball right now, those guys are as good as anybody in baseball," said outfielder Ryan Braunabout the quality of Milwaukee's pitchers.
He's not wrong. Let's start with Woodruff here, since he's long been a starter in the minors -- over 80 percent of his pro starts have come as a starter -- and he showed he could do it in NLDS Game 1. He's shown almost no platoon split in his brief time in the bigs so far, which would let Roberts mix and match as he pleases. 

In the NLDS, Burnes followed, and he's got fastball spin in the 95th percentile of righties. That makes for more interesting Los Angeles decisions, because you'd think Bellinger against righties would be a given, but he hit just .111 with a .111 slugging against high-spin righty four-seamers. It might be a weakness. Follow with Josh Hader, Corey Knebel, Joakim Soria, and Jeremy Jeffress as needed. 
Game 3: Start Gonzalez
Yes, Miley was a very nice find on a Minor League contract. Yes, he started ahead of Gonzalez in NLDS Game 3. But there was an argument in that case, because the game was at Coors Field, and because Miley keeps the ball on the ground a little better than Gonzalez does, which is important in that park. (Plus, the Rockies lineup isn't strong.)
Otherwise: Gonzalez is just a better pitcher. As effective as Miley was this year (2.57 ERA), he just had a bottom-10 strikeout rate (14.8 percent) among pitchers who threw 80 innings. Looking back at the last two years, because Miley didn't really pitch enough this year to make any platoon splits worthwhile, Gonzalez allowed a .547 OPS to lefties, while Miley was at .649. Against righties, Gonzalez has a .722 OPS; Miley has an .806 mark.
Either way, neither is going deep. Try to get four or five innings and then follow, again, with what ought to be a well-rested bullpen.
Game 4: Tandem starters. Miley, then Guerra or Peralta
Obviously, this depends on how things have gone. Chacin on short rest is possible, though not optimal. There's an argument for Chase Anderson, but he hasn't pitched since Sept. 18 at this point. There's even a case to be made for another bullpen situation, though that's not idea in the middle of what would be three games in a row in Los Angeles. 
Instead, we'll say that Counsell will do a different version of a bullpen game, in a best attempt to get Roberts to exhaust his bench. While Miley's new cutter did help his platoon issues this year, he's long been better against righties than lefties. Peralta actually was much better against righties (.397 OPS) than he was against lefties this year (.865), while Guerra has had almost no splits at all over the last three years -- and he struck out eight hitters without allowing a walk or a run in five September games after moving to relief.

Mix and match, is the point, perhaps with lefties Xavier Cedeno or Jennings if either makes the roster, and hope that some of your late-inning weapons are rested enough to contribute.
Games 5-7: Wing it
"You can't predict baseball," as the saying goes, and so it's foolish to wonder how things look by this point. The series could be over, for one thing, and it's anyone's guess how the pitching will work out over the first four games. The only thing you can really plan upon here is that any plan you hope to have will quickly be replaced by the plan you need to improvise. 
The Brewers are far from a traditional pitching staff, and the Dodgers have a powerful yet flexible lineup. It won't be easy for either side. That's sort of the point, though, isn't it? You don't get one step away from the World Series because things have been easy.