Nationals starting pitcher Stephen Strasburg has been placed on the 15-day disabled list and -- brace yourself, D.C. fans -- it's with soreness to his throwing elbow. Gulp.

Here are five things to know.

1. Strasburg has struggled recently

Through Aug. 1, Strasburg was 15-1 with a 2.63 ERA. In his last three starts, he's 0-3 with a 14.66 ERA. He's struck out 18 in the 11 2/3 innings and velocity wasn't really down, but he was ravaged by opposing hitters to the tune of a .414/.462/.776 line. It's true that one of those starts came in Coors Field, but he was knocked around in all three starts, including by the Braves on Aug. 12.

Could the elbow injury explain it? Sure. Sometimes command (location, not necessarily control in terms of balls and strikes) goes before velocity when there's an injury.

Stephen Strasburg has an elbow injury. USATSI

2. There's injury history here

Back in 2010, Strasburg tore the ulnar collateral ligament in his right elbow, forcing him to undergo Tommy John surgery and miss most of 2011. Then in 2012 came an excellent season with the notorious (and overblown) "Strasburg Shutdown." He hasn't really had elbow issues since, but knowing the history, any elbow injury is worrisome.

For now, it sounds like the Nationals are just being careful with Strasburg, as Joel Sherman of the New York Post reports this isn't structural and is just "a touch of inflammation."

So that means for now that this should only be a short-term problem. And ...

3. The Nats have the depth to absorb this in the short term

Max Scherzer, Tanner Roark and Gio Gonzalez are fixtures in the Nationals' rotation. Reynaldo Lopez has made four starts and flashed good upside in his last two. Joe Ross has a shoulder injury and could be back at some point in September. We caught a glimpse of Lucas Giolito earlier this season and he's been excellent in his last two starts at Triple-A.

For now, 24-year-old A.J. Cole will take over for Strasburg in the rotation. He's 8-8 with a 4.26 ERA and 1.33 WHIP in 22 Triple-A starts.

Regardless of how things progress, the Nationals have plenty of options in the rotation without Strasburg for the next several weeks. There are seven names listed above for five rotation spots.

4. The NL East is still the Nationals' to lose

Entering Monday, the Nationals boast an 8 1/2 game lead in the NL East with just 39 games to play. SportsLine has the Nationals with a 99.6 percent chance of winning the division.

Let's put it this way. If the Nationals go 19-20 the rest of the way, they'll end up 92-70. In order for the second-place Marlins to tie them, they need to go 27-11. Do those figures seem likely?

5. A long-term injury is a crushing blow, though

Looking ahead to the playoffs is a different story. If Strasburg returns from injury and pitches back to form, the Nationals could run out an very imposing Scherzer-Strasburg-Roark trio in the NLDS. Then, if they get to the NLCS or World Series, those three could be joined by maybe Gonzalez, Lopez or Ross, if he's healthy by then.

What if the elbow issue lingers or even gets worse though? That doesn't seem likely right now, but it's certainly possible. Well, that's a game-changer.

Removing Strasburg from the equation drastically softens how the rotation would look in a seven-game series. They would be counting on an inconsistent Gonzalez along with either a rookie (Lopez) or someone who missed significant time with a shoulder injury (Ross) to do some heavy lifting.

Let's also keep in mind that the Nationals are 18-5 in Strasburg starts this season and 55-45 when he doesn't. Heading into the postseason without that weapon obviously makes a big difference.