Shortstop Corey Seager is not on the Dodgers’ NLCS roster after injurying his back during the series against Arizona. (Ross D. Franklin/AP)

The Los Angeles Dodgers swept their way into the National League Championship Series. The Chicago Cubs had to endure a harrowing fifth game against the Washington Nationals, travel cross-country — and then have their flight diverted to Albuquerque because of an ill passenger. They arrived at their hotel Friday afternoon, some 13 hours after they left Nationals Park.

And yet, the Cubs gained a significant advantage before Saturday's Game 1.

The Dodgers left shortstop Corey Seager, an all-star who hits in the second spot in the order, off the roster for this series because of a back injury suffered Monday in the third game of their division series against Arizona.

"This sucks, to be honest," Seager said before the game at Dodger Stadium. "Obviously you try to be the best teammate that you can right now, try not to be a distraction."

Seager's injury came on a slide at second base in the first inning of Game 3, a play he called "a very normal slide." He remained in the game, but woke up Tuesday morning feeling extremely stiff. The Dodgers gave him an epidural to help relieve the symptoms, and Andrew Friedman, the team's president of baseball operations, said Seager felt better each day.

"He has progressed," Friedman said. "But just not rapidly enough that we felt comfortable with the risk."

The injury put 28-year-old Charlie Culberson at shortstop for Game 1 against Cubs lefty Jose Quintana. Culberson hit just .154 in 15 games with the major league club this season and spent most of the season with Class AAA Oklahoma City.

"He's a really good defender," Friedman said. "He has handled left-handed pitching pretty well, and just adds versatility to our group."

The Dodgers could also use Chris Taylor, who started 10 times at shortstop, or Enrique Hernandez, who started there 16 times, as replacements for Seager in this series. Both have been valuable utility players for Los Angeles over the course of the season. Taylor hit .288 with 21 homers in 140 games, and Hernandez hit just .215.

So removing Seager is a significant blow for a team that scored 52 fewer runs than the Cubs over the course of the season.

After winning the National League's rookie of the year award in 2016, Seager hit .295 with 22 home runs and an .854 on-base-plus-slugging percentage. An elbow problem kept him out of the lineup for two weeks in September, but the Dodgers expected him to start every game of their playoff run.

The only way Seager could return during the NLCS would be if another Dodger were injured. In that case, Friedman said the club would have to evaluate how much Seager had improved in the interim. Seager will not travel with the team to Chicago for Games 3-5, which are Tuesday, Wednesday and Thursday.

"It's not anything that is of concern as we look forward in terms of next spring training," Friedman said. "Obviously that's not what any of us are focused on right now. We're optimistic that he'd be ready for the next round. That being said, we're not going to venture past the day-to-day."