Everything you need to know as Nationals and Dodgers meet in Game 4

Clayton Kershaw and Joe Ross will start Game 4 in Los Angeles. Getty Images

With their season on the line, the Dodgers will send Clayton Kershaw to the mound on three days' rest for Game 4 against the Nationals. Washington will counter with right-hander Joe Ross. Is the series headed back to Washington for Game 5 or will the Nationals be on their way to the NLCS?

Go inside the numbers and matchups that will decide Tuesday's game, then vote for which team will win at the bottom of the page.

Inside the pitching matchup

When Joe Ross is on the mound: Ross is a two-seam fastball/slider guy whose fastball runs up to 93-94 mph. He doesn't throw his changeup much and his slider has good 12-to-6 break and held righties to a .174 average. The problem is lefties destroyed his fastball at a .441/.505/.591 clip. He wasn't homer-prone, but he generates so few swings and misses against lefty hitters that it results in a high average allowed. You may have heard that the Dodgers' lineup leans left-handed.

The other concern is that Ross has pitched just 9⅔ innings since returning from a sore shoulder that sidelined him for most of July and all of August. He allowed one run in four innings in his final outing but threw 90 pitches. If he starts, expect a quick hook. -- David Schoenfield

When Clayton Kershaw is on the mound: Great fastball, great curveball, great slider, great command, great deception ... you know all this. Kershaw has cut his fastball rate from 70 percent in his early years to 60 percent by 2013 and is now down to just over 50 percent. He now throws his slider twice as often as his curve. Batters don't really do much with any of the three pitches.

His start in Game 1 was a struggle, with 101 pitches in just five innings. The Nationals were patient -- some believe the best approach against Kershaw is to attack fastballs early in the count -- and Kershaw's command was just a little off. The key was not chasing anything off the plate, and the Nationals had a chase rate of just 22 percent compared to 33 percent against Kershaw over the season. That's 11 pitches they didn't swing at that Kershaw usually gets swings on.

Jayson Stark made a great point about Kershaw in his piece on Monday: He's so good in the regular season that when he allows even three runs, it's a bad game. That creates enormous pressure to pitch great every time out. Does the mental weight of that catch up to him by October? Are our expectations just too high? He pitched on three days' rest last year and was great, holding the Mets to one run in seven innings in extending that series. -- Schoenfield

Player in the spotlight

Jayson Werth. He had some terrific at-bats in Game 3, including a big home run in the ninth off Kenley Jansen. He has a .500 OBP in these three games and crushed lefties during the regular season at a .322/.411/.620 clip. He'll be a tough out. -- Schoenfield

What will decide Monday's game

Corey Seager has three hits in this series, all for extra bases, and all three of them have come on pitches on the outer half. He has seen 18 pitches out there, swinging at nine of them and not missing any of them. But he has seen 29 pitches on the inner half, and he has missed seven of his 17 swings against them (41 percent). He's 0-for-7 with all three of his strikeouts in at-bats ending on pitches on the inner half. -- ESPN Stats & Info

Choosing sides: Who will win?

The Nats clearly have Uncle Mo on their side right now. But good ole Mo is only as good as the next day's starting pitcher. In this case, that would be Joe Ross. Nothing against Ross, but he's no Clayton Kershaw. L.A. leverages the audio earthquake that is Dodger Stadium and evens up the series. -- Eddie Matz

With so many injuries and roster uncertainty, this whole season has been a back-to-the-wall proposition for the Dodgers, so they've been through this already and are probably confident they can force a deciding Game 5. Expect all of that left-handed Dodgers hitting talent to be unleashed against right-hander Joe Ross in front of a home audience. -- Doug Padilla

Where the series stands

Well, the Dodgers have to win! All hands on deck. If it's a low-scoring game, Dusty Baker's ability to mix and match his bullpen will be a key. So far, so good, as the Nationals' pen has tossed 12⅓ scoreless innings. -- Schoenfield