Olney: Harper's timing, Kershaw vs. Martinez keys to NLDS

Bryce Harper finished the season with 29 homers despite missing 40 games with knee and calf injuries. Steve Mitchell-USA TODAY Sports

Here's what to watch as the National League Division Series get underway.

Bryce Harper vs. his timing

The slugger is back in the lineup after returning from a knee and calf injury, but in the last days of the regular season, he still seemed to be searching for his timing. He had three hits in 18 at-bats, with no extra-base hits, two walks and seven strikeouts. As the Nationals begin this series, he will continue to be something of a wild card.

The Cubs will assess Harper's swing and adjust their pitching plan as the series progresses, but for now, there does not appear to be a reason for Joe Maddon to have his staff pitch around Harper, in the way that he did early in the 2016 season. Harper will probably get some pitches to hit in this series.

Trea Turner vs. Willson Contreras

The Nationals' shortstop is one of a handful of elite base-stealers, with the speed, acumen and special competitive arrogance needed to run successfully even when opposing teams know that he’s going to go. He has 46 steals in 54 attempts this year, and in his career, he has 81 steals in 97 attempts, an excellent ratio for someone so young. (It’s probably not a coincidence that Washington’s first base coach is Davey Lopes, who is generally viewed as the base-stealer whisperer -- someone who sees tells in what pitchers do and goads his charges into taking bases).

Turner will have to run, however, against Willson Contreras, who might have the strongest throwing arm of any catcher in baseball -- so powerful that he'll throw out runners even when working with pitchers slower in their delivery. When Arrieta worked with Miguel Montero in seven starts, opponents swiped 12 bases in 12 attempts; in 16 games with Contreras, runners tried to steal only eight times and were thrown out on three.

In a close game, Turner will look to run, to alter the game with his speed, and Contreras will be looking for the opportunity to throw. These two players have extreme confidence in their particular skills.

Jake Arrieta and Max Scherzer vs. their hamstrings

The two Cy Young Award winners have developed their excellence through a devotion to diligent physical training, and their regimens have constructed the foundations of unusual deliveries. Arrieta is 6-foot-4 and weighs something in the range of 225 pounds and throws with a crossfire motion, stepping toward the third base dugout as he drives fastballs homeward. Scherzer seems to throw as hard as he possibly can on every pitch, grunting in his effort; earlier in his baseball life, the sheer violence of his delivery scared teams away (to their regret later).

For either of these pitchers to have a breakdown in his physical machinery is a major concern, because of their respective effort levels in how they pitch. That could be why the Cubs backed up Arrieta in their rotation, and the Nationals pushed Scherzer back, with Stephen Strasburg starting Game 1. The clubs don't know if they will hold up from start to start. Given the limits of the remaining calendar, it may be that the best that teams can hope for is for Arrieta and Scherzer to give them one quality outing in each series -- and that they can get through five or six innings.

Stephen Strasburg vs. the weather

When it’s hot and miserable, Strasburg’s face reddens and it’s as if all the moisture drains out of him. He grew up in Southern California, in a place of lower humidity, and whether it’s because of this background or because of his DNA, Strasburg has long struggled to stay hydrated on bad days. The Nationals must be a little relieved, then, that the series against the Cubs is the stuff of prime time and Strasburg’s start in Game 1 (and any other start in this series) will be in the evening, after the setting of the sun.

With Scherzer hurting, Strasburg becomes the most important player on the Washington roster. The Nationals must win at least one of his starts, and on paper, they seemingly have an advantage on the days when Strasburg pitches, so long as he can get through his work without having the heat-related problems that have shortened a lot of his past outings.

The Nationals vs. the onus of history

The Cubs played better down the stretch and separated themselves from the pack in the NL Central to reach the postseason in the first year after they won the World Series, and they seem to be entering this October tournament pressure-free. There is no more talk about billy goats or bearing the hopes of generations of Cubs fans or 108 years without a title.

The Nationals, on the other hand, enter this year’s playoffs with a countdown clock hanging over them. Harper is only 13 months from reaching free agency, and it may be that this particular group of Washington players have only two more Octobers together -- after a lot of recent playoff frustration. The Nationals reached the postseason in 2012, in the season in which Strasburg was shut down, and they were knocked out in the Division Series. They got back to the playoffs in 2014, and once again, they didn't get through the first round. Last year, they had an epic five-game battle with the Dodgers in the Division Series, and lost.

Washington has a lot of great players, including some future Hall of Famers, and they've been demonstrably better than the Cubs during the regular season. But for the first time in a long time, the Cubs can say this: Their success and postseason experience will be a weapon, against a team that is desperate for its first October success.

The Cubs vs. their defensive limitations

In 2016, the Cubs were an historically great defensive team, with 82 Defensive Runs Saved, 31 more than the second-best team. This year, the Cubs ranked fifth among 30 teams, with 30 Defensive Runs Saved, and Maddon has some imperfect defensive options to chose from -- especially in the outfield. Jon Jay finished the season strongly at the plate, but he is limited as an outfielder. Ian Happ had a tremendous rookie performance, but Happ, an infielder for most of his time in pro ball, tends to make mistakes in reading fly balls when he plays center. Only two outfielders rated lower than Kyle Schwarber in Defensive Runs Saved -- Matt Kemp and Khris Davis. Zobrist, 36, will catch what he can get to, but like Jay, he’s not a plus defender. Zobrist played only 360 innings in the outfield this season, and yet ranks in the bottom third in Defensive Runs Saved.

Kris Bryant vs. Sean Doolittle

As some evaluators debated the wisdom of the recent industry obsession with launch angle, Bryant has always been held out as a outlier. As a child, he built an uppercut into his swing -- he liked the idea of hitting home runs, he recalled, and was rewarded for them by his grandfather -- and so he has the ability to get to pitches in the upper half of the strike zone and lift them.

Doolittle also is an outlier. He probably works near or at the top of the strike zone as much as any reliever in baseball, an attack plan of extreme success. In 30 innings with the Nationals, he’s allowed just 21 hits and eight walks, with 31 strikeouts and an ERA of 2.40.

If Doolittle and Bryant face each other, it will be a test of opposing strengths: Doolittle’s northern-hemisphere fastball against Bryant’s powerful uppercut.

Robbie Ray vs. the wild-card game ripples

As they dominated the Dodgers in the final six games between the two teams, outscoring L.A. 40-13 while going 6-0, it seemed the Diamondbacks were setting up an ideal situation for themselves: If they won the wild-card game with Zack Greinke, then Ray -- a lefty who totally dominated the Dodgers in four outings during the regular season -- could start Game 1 against Clayton Kershaw and then perhaps Game 4.

But Greinke was knocked out early in the wild card and Diamondbacks manager Torey Lovullo had to call on Ray to help beat the Rockies. Now Ray won't start Game 1; rather, he's likely to get the ball for Game 2 and, if necessary, Game 5. It's not what the Diamondbacks would’ve preferred, and additionally, Greinke’s quick exit from the wild-card game raises even more questions about his fade late in the season. Arizona is dangerous against the Dodgers, but there may be a clear advantage with the Dodgers' rotation as this series begins.

The Dodgers vs. the 7th- and 8th-inning bullpen challenges

Dave Roberts' team ran away with the NL West, despite the late-season slump, and his bullpen has been really good. Its ERA of 3.38 was the fourth best in baseball. But at the end of the season, the Dodgers' relief situation in front of closer Kenley Jansen seemed surprisingly unsettled, with Ross Stripling, Tony Watson, Tony Cingrani, Pedro Baez, Josh Fields and Walker Buehler all auditioning for various roles. The Dodgers' depth was an enormous advantage for them all season, but interestingly, in the postseason L.A. might revert back to the old-school formula of relying on starting pitchers to get as as deep into the game as possible, with the last three to six outs turned over to Jansen.

Brandon Morrow was a strong option for the Dodgers all season and he could play a crucial bridge role this month, with his 100 mph fastball. Morrow did not allow a run in his last nine appearances of the regular season, and he surrendered a run in just one outing after Aug. 12.

Fernando Rodney vs. the Dodgers' hitters

There's no getting around this: In an October filled with the best relievers in baseball, Rodney is the hope-and-pray closer of this postseason, and in a big spot, he might need some Pixie Dust to get through the Dodgers' lineup. He pitched 8 1/3 innings against the Dodgers in 10 games, allowing eight hits, seven walks and eight runs, for an 8.64 ERA. In his brief career, Corey Seager is 3-for-4 against Rodney; Justin Turner is 2-for-4, Yasiel Puig is 3-for-8. Arizona could probably use as much padding as possible for those times when Rodney is called on to close out the Dodgers.

Clayton Kershaw vs. J.D. Martinez

Kershaw is perhaps the greatest pitcher of all time, and coming off another excellent season -- and he's left-handed. Martinez has destroyed left-handed pitching this season, batting .376 with an .892 slugging percentage. Seriously, that is not a misprint: 10 doubles, 1 triple and 12 homers in 93 at-bats against lefties, with a 1.356 OPS. In Martinez’s career against Kershaw, he's 3-for-8, with a double, a home run and a walk.