The Cardinals are set to begin a four game series against Bryce Harper’s Nationals, and they’ll have to decide whether or not they should pitch to the slugger.

The division rival Chicago Cubs officially put the world on notice about how teams plan to pitch to Bryce Harper. Actually, they informed everyone that teams don’t plan to pitch to Harper.

Over the course of two games against the Cubs, the star player went 0-0 in 11 plate appearances, getting 9 walks, four of which were intentional, one sacrifice fly, and one hit-by-pitch. The Cardinals now get to face Harper, but should they follow in other team’s footsteps and refuse to pitch to him?

Let’s start here: left-handed pitchers need to pitch to him. Harper is still better than most hitters against southpaws, but he isn’t one of the best in the game. Last year was by far his best season as a major league player, and he only hit seven home runs in 189 plate appearances against lefties. In 162 games, that’s about 25 home runs.

That’s not a bad number by any means, and the Nationals will certainly take the .318 average that he had against lefties, but a player like that is not worth putting on base every time just to avoid a worse outcome. Jaime Garcia, Kevin Siegrist, Tyler Lyons, and Dean Kiekhefer need to go after Harper unless there is a runner in scoring position with first base open.

Against right-handed pitchers, things get a little more complicated. Last year, Harper hit 35 home runs in 465 plate appearances to go along with a .335 average. That projects to approximately 52 home runs in 162 games. Harper has continued to hit right-handed pitching well this year, albeit with a much lower average. Despite Harper’s hitting, the Nationals have struggled in this area.

The Nationals currently rank 23rd in wOBA against righties, even though Harper ranks 28th in this area amongst players with at least 100 plate appearances. Although the statistic isn’t perfect, wOBA is a modified version of on-base percentage that accounts for the true value of each type of hit (i.e home runs count more than triples which count more than doubles, and so on).

If Harper were to walk every single time, then his wOBA would be .690. His actual wOBA against righties this year is .399 and was .478 last year. For reference, Barry Bonds’ best wOBAs were around .540. These numbers would seem to indicate that it was not even a good idea to walk Bonds every time he got up to the plate, but there is more to the story.

Part of the reason for pitching around Harper (and Barry Bonds) is that there are no feared hitters behind him. Daniel Murphy is playing well now, but throughout his career he has just been an above average player; there is no reason to think that he is suddenly one of the best hitters in the game. Outside of Harper, Murphy, and Wilson Ramos, no Nationals hitter has a wOBA above .310 (which is considered below average) against righties.

Does that mean that Harper should be walked? Probably not. The wOBA numbers assume that an average player is hitting behind you. In other words, that .690 only helps us understand the situation if everyone behind him plays like an average player. If they play better, then the value of lesser hits (singles or walks) increases, but if they play worse then the value of home runs increases.

Even with Murphy included, the players behind Harper are certainly below average, but not horrible enough to make up for the 200-300 points in wOBA that you’re giving the player. Ryan Zimmerman and Anthony Rendon have been pretty bad, but they’re not as bad as they need to be to make this strategy make sense. For that, you would need about three Jayson Werths batting behind Harper. Seriously, it would be worth it at that point.

Mike Leake, Adam Wainwright, Michael Wacha, and the right-handers in the bullpen will certainly need to be careful when pitching to Harper, but they should not just automatically walk him. I have no problem with pitching around the edges and hoping to get him to chase instead of throwing clear strikes, but the numbers don’t back up the idea that putting Harper on every time is smart.

We can all try to get Dusty Baker to bat Werth, Michael Taylor, and Danny Espinosa behind Harper (I would walk him then, too), but until then, lefties need to attack Harper and righties need to pitch carefully without giving away free passes.

Photo captured by Jeff Curry – USA TODAY Sports