Quick, what do Ryan Zimmerman, Ross Detwiler, Stephen Strasburg, Drew Storen, and Bryce Harper have in common? If you have been following this franchise as closely as I have then you would know that they are five of the Nationals eleven first round picks made since the team moved to DC. Of the players that the Nationals have drafted and who aren't on the major league roster one is retired and another never signed. Chris Marrero, Anthony Rendon, Alex Meyer, and Lucas Giolito are all still in the minors with Marrero having made it to the majors last season and it being far too early for any of the latter three.
As far as drafting has gone the Nationals have done a good job. Having five players from a five year span of first rounds on the roster sounds like a high percentage, but it isn't the entire story. Since moving to DC the Nats have also drafted Danny Espinosa, Jordan Zimmermann, Craig Stammen, Steve Lombardozzi, and Tyler Moore. The Nationals also held onto Ian Desmond and Roger Bernadina who were in the Expos farm system when they made the move to DC. Of the players currently on the 25 man roster 12 of them are from the Nats farm system.
It can also be said that without a strong farm system Gio Gonzalez wouldn't be on the Nationals. Both Derek Norris and Tommy Milone, who were part of the Gio trade, have contributed to a contending Oakland team. As the reputation of the Nationals farm system grows around baseball it will help them to make more trades.
As it currently stands the Nationals farm system isn't thought to contain much talent with Anthony Rendon having missed much of the year with an ankle injury and 2012 first round pick Lucas Giolito needing Tommy John's surgery. Alex Meyer is a big tall hard throwing right hander with top of the rotation talent and Brian Goodwin looks like he could be a five tool centerfielder. All four of those guys have star level ceilings and it is rare for a farm system to even have four that good, especially in a year when their number one overall talent graduated to the majors.
When looking at the Nationals system don't forget names like Sammy Solis who missed the entire season due to Tommy John's surgery, Eury Perez who as he dropped off the radar rose through the system and is now hitting .336/.378/.397 with 19 steals in 24 tries at the age of 22 in AAA, Sandy Leon the catcher who briefly filled in for the Nationals during the great catchers epidemic of 2012, or Robbie Ray who has had a down year but is still only 20 at high A. None of these players have a great chance to be a star in the majors, but all of them look like they could be productive major leaguers and help a team in some capacity.
Eury Perez very well could be the Nats future fourth outfielder once Bernadina gets too expensive for that role. Ray and Solis could grow into back of the rotation starts are end up as trade bait for a veteran player, and Sandy Leon has already demonstrated his value as a back-up or even starting catcher for somebody down the road.
Just under half of the Nationals current 25 man roster are homegrown and with the types of players they have in their farm system combined with their future needs it looks like that percentage won't change much or could even be on the rise with Rendon, Meyer, and Goodwin all expected to make an impact in the next season or two. The Nationals took a calm and steady approach to building a team through scouting and the draft, and now in 2012 they are getting an early return on their investment.