However, the Giants will start a pitcher who is arguably just as good, as right-hander Johnny Cueto (18-5, 2.79 ERA) goes against Cubs left hander Jon Lester (19-5, 2.44 ERA) in Game 1 of the best-of-five series.
"I think you look at Johnny and Bum, and they're both number ones," Giants manager Bruce Bochy said after a lengthy travel day and late arrival in Chicago on Thursday. "We'd be comfortable with them in any game. The fact that we used our guy (Bumgarner) to get here and then we have Johnny, that's a nice luxury. And I like the way the rest of them are throwing.
"It's nice to have a rotation with this depth."
Bumgarner (15-9, 2.74 ERA) worked a complete-game four-hitter Wednesday in the Giants' 3-0 wild-card victory over the New York Mets at Citi Field.
The Cubs likely will have to contend with him as a possible Game 3 starter when the series shifts to AT&T Park on Monday. Bochy said he still had not decided on the rotation beyond Friday.
Cueto, the winningest Giants starter this season, won his past four outings since a Sept. 4 no-decision in the Giants' 3-2 loss to the Cubs at Wrigley Field -- his only appearance against Chicago this year.
He allowed one run on five hits, struck out five and walked just one over seven innings.
Cueto missed a turn on Sept. 25 due to a left groin strain but returned to strike out 11 and allow two runs in a seven innings during a win over the Colorado Rockies on Sept. 29. He said Thursday through a translator that he feels fine.
The Cubs' NLDS rotation was a matter of who has pitched well and where.
Lester fell short of his first 20-win season but still had his best winning percentage (.792), matched his 2010 career high in victories and had quality starts in all 15 home games this season.
"He earned it," Chicago manager Joe Maddon said.
"A lot of it is based on recent productivity and the fact that Jon's just nailed it and Kyle has nailed it," Maddon said. "They've also been good at home, where Jake has also been good on the road. It kind of morphed into that the last couple of weeks."
Lester is 4-1 with a 2.25 all-time ERA against San Francisco, including 1-1 with a 4.63 ERA this season. He beat the Giants in a complete-game, 2-1 decision on Sept. 2 at Wrigley.
Cubs starting pitchers topped the major leagues with 81 victories, a 2.94 ERA and a .212 opponents' batting average. It was just the second time since 1913 that Chicago starters earned 81 wins. The 1945 Cubs staff had 87.
The Cubs and Giants meet in the postseason for only the second time. San Francisco claimed a 4-1 series victory in the 1989 NL Championship Series.
The Giants have won 11 consecutive postseason series, including wild-card victories in 2014 and on Wednesday.
Chicago (103-58) posted the major league's best record in 2016 and went 4-3 against San Francisco (87-75), including 3-1 at Wrigley Field.
Prediction and Pick to Win Series
The Cubs had the major league's best record for a reason. They have a loaded pitching rotation with Lester, Hendricks, and Arrieta and a deep lineup. Bumgarner will be tough to beat in his likely game 3 start but the Cubs will win the other games. Cubs win the series 3-1.