Nationals, Giants in crucial, must-see series

Maybe the best series of the week will take place on the left coast as the Washington Nationals take on the San Francisco Giants in three games in a battle of first-place teams. What's interesting is that these two teams known for their pitching actually rank 1-2 in the National League in runs scored since the All-Star break (Nationals first, Giants second). While Ryan Zimmerman, Adam LaRoche and Mike Morse have combined for 23 home runs since the break and Buster Posey is the hottest hitter in baseball, it's still the pitching matchups that make this series so intriguing.

Could we be seeing a playoff preview? I believe so. Let's take a closer look at some things to watch in each game.

Monday: Gio Gonzalez versus Ryan Vogelsong

Here's an amazing fact about Ryan Vogelsong: He hasn't allowed more than four runs in a start all season -- and he's done that just twice. Basically, he hasn't had a bad start; his 90 percent quality-start percentage (19 in 21 starts) leads the majors. Going back to 1990, only one pitcher has started 20 games and achieved 90 percent quality starts -- Greg Maddux in 1994, with 24 quality starts in 25 games. No wonder he had a 1.56 ERA. But Maddux's quality-start percentage was helped by nine unearned runs; he allowed five runs in four starts.

Vogelsong has an ERA of 2.27 but his detractors will point to sabermetric numbers that don't back that up: He has a 3.68 FIP and 4.42 xFIP. Those numbers suggest that because he doesn't have a high strikeout rate and his home run rate is below what you would expect from a fly ball pitcher, his ERA should be higher. His .246 average on balls in play is third lowest in the majors and his 84.2 left-on-base percentage is best among starters. But his detractors have been waiting for him to fall since last season and it hasn't happened yet. Coincidentally (or not), he had the fourth best LOB percentage last season.

OK, so Vogelsong's not overpowering. All he does is getting batters out. Two reasons: His changeup against lefties and his curveball against righties. Here are his heat maps for those two pitches. In 61 plate appearances ending with his changeup, lefties are hitting just .207. In 56 plate appearances ending with the curveball, righties are hitting just .135 with no home runs. Luck? Or skill?

Tuesday: Jordan Zimmermann versus Madison Bumgarner

Right behind Vogelsong in the quality-start department is Zimmermann, with 20 in 23 starts (87 percent). With a 2.35 ERA, he's right behind Vogelsong in that stat, as well. Zimmermann is coming off his first double-digit strikeout game of 2012, with 11 in six innings … OK, it was against the Astros. He's also allowed more than two runs just once in his past 10 starts. If there's something to nitpick on Zimmermann's season it's that he doesn't go deep into games. Held to a tight pitch count (he hasn't thrown 100 pitches in a game since June 22), he hasn't pitched more than seven innings all season and hasn't gone more than six in his past six outings.

Zimmermann throws harder than Vogelsong, with an average fastball velocity reaching 94 mph. Impressively, he throws it with great precision, sort of a right-handed version of Cliff Lee. His walk rate is sixth best among all starters (Bumgarner is 11th in walk rate). With great control of the fastball, Zimmermann can then go to his off-speed pitches. He throws a slider and curveball, although he doesn't even use the curve much against right-handers. Here are his heat maps with the curve versus lefties and slider versus righties. In 56 PAs ending with the curve, left-handed batters are hitting .180. Righties are hitting .240 with a 25 percent strikeout rate in 108 PAs against the slider.

Wednesday: Stephen Strasburg versus Tim Lincecum

Strasburg is tied with R.A. Dickey for the NL strikeout lead, although he's pitched 29 fewer innings than Dickey. Strasburg's average fastball velocity of 95.8 mph leads all major league starters, just ahead of David Price. But like a lot of hard throwers, the fastball alone isn't always enough. In fact, when Strasburg has been forced to come in with a fastball, left-handers have actually handled it. Here are Strasburg's numbers against left-handers on his three primary pitches on plate appearances ending with those pitches:

Fastball (178 PAs): .325/.389/.452, 14 percent K rate

Changeup (67 PAs): .234/.269/.375, 46 percent K rate

Curveball (37 PAs): .143/.162/.229, 49 percent K rate

His numbers against right-handed batters:

Fastball (151 PAs): .204/.273/.372, 26 percent K rate

Changeup (34 PAs): .129/.206/.226, 59 percent K rate

Curveball (70 PAs): .121/.171/.167, 47 percent K rate

It could be small sample-size results, but so far it appears left-handed batters see the ball much better off Strasburg, at least his fastball. The Giants would be wise to stack their lineup with as many lefties as possible. Regardless, Lincecum will likely have to bring his A-game. He does have a 3.66 ERA at home, as he's allowed just three home runs in 12 starts. He's been better in all environs of late, with a 2.72 ERA over six starts. I have a feeling we'll see two guys at their best; look for a low-scoring game in the series finale.