We love rivalries. Rivalries are fun.

But we can't fake them, and we can't force them. We can't demand them.

The Nationals have tried hard to declare that the Phillies are their rival. They've tried hard to demand that the Phillies be their rival.

And here's what the Phillies say, in advance of the teams meeting this week in Philadelphia:

"We don't approach them any different than the Braves or the Mets," Phils third baseman Placido Polanco said. "The rivalry for us is the whole division."

Polanco and the Phillies didn't even take offense when ex-teammate Jayson Werth spouted off in an email to the Washington Post.

"I am motivated to get back quickly and see to it personally those people never walk down Broad Street in celebration again," Werth wrote.

Strong words?

"He told me, 'I'm sorry, I never should have said that,' " said Polanco, who accepted the apology and noted that Werth was on pain-killers because he had just broken his wrist.

To be sure, a rivalry could develop between the Phillies and Nationals. Some of the elements already exist.

The ballparks are just 134 miles apart, close enough for fans to make the drive. The teams play in the same division, and while the Phillies have won it five years running, the Nationals are seen as up-and-coming and as an ever-increasing threat.

The Nationals got tired of seeing Phillies fans take over Nationals Park. The marketing people got involved.

Werth, who won the World Series with the Phillies, became the Nationals' first big free-agent signing. Ex-Phils closer Brad Lidge is also a National, although like Werth he's on the disabled list and will miss this week's series.

Then there's what happened two weeks ago, when the teams met in Washington and Cole Hamels threw at Bryce Harper (and admitted it).

Fortunately, Hamels will also face the Nationals this week (on Wednesday night). Unfortunately, Nationals-Phillies isn't yet a highly-anticipated rivalry.

Not in Philadelphia, anyway. As of Sunday morning, I had no problem finding 10 seats together for Monday night's game, just 32 rows behind the Nationals dugout.

The games will sell out, as all games at Citizens Bank Park do. As Polanco said, it's no different than when the Braves or Mets are there.

Still, this is hardly viewed as a can't-miss series in Philadelphia.

No, it's not a big rivalry. Not yet.

Perhaps this week will change things.

On to 3 to Watch:

1. The Orioles loved ruining the Red Sox season last September. Their fans loved it. So is this a rivalry? Not really. But the Red Sox are back in Baltimore for the first series since then, for Red Sox at Orioles, Monday night (7:05 ET) at Camden Yards. It'll be interesting to see if this is the point when Orioles fans begin to believe and begin to show up in large numbers.

2. One thing about Hamels: That first inning on May 6, when he hit Harper and Harper eventually stole home, didn't seem to negatively affect the Phillies left-hander. In 21 innings since, Hamels has allowed just four runs (a 1.71 ERA), with five walks and 21 strikeouts. Harper and the Nationals get another chance at him in Nationals at Phillies, Wednesday night (7:05 ET) at Citizens Bank Park.

3. Tigers-Indians should be a rivalry. The cities are close, and the teams play in the same division. But they've basically never been good at the same time, so they've basically never had a late-season series that was meaningful for both teams. Maybe this is the year that changes. And maybe, with Detroit in town for a series that includes Tigers at Indians, Thursday afternoon (12:05 ET) at Progressive Field, this is the week that Indians fans start noticing their team. Maybe they just show up to boo closer Chris Perez, who ripped Indians fans for booing him -- and for failing to show up. "Nobody wants to play in front of 5,000 fans," he told reporters. Everybody should want to see Justin Verlander, who starts Thursday against Justin Masterson.