I, like nimajneb, took a look at the draft performance of teams. My version looked at time played during the regular season, which was easily available. It would be interesting to see how Open Cup and CCL games play into this, as I'm guessing that would improve the Sounders numbers. This also does not take into account trades that occur once a pick has been selected, such as the Sounders trade for Andy Rose. All data is from 2009-2013, which covers the time since the Sounders have been a part of MLS.
This first graph shows the teams which have the the highest average MLS minutes in the regular season by their average draft picks by round. For example, DC United has almost 1,800 minutes per season from their average first round draft pick. The teams on the left side of this graph have clearly gotten a significant contribution from their draft picks, while those on the right side have gotten fewer first team minutes from their draft picks. The Sounders are the second from the bottom in this regard, which could have several potential reasons.
One issue could be the location of these draft picks. The earlier in the round, especially the first round, a team drafts, the better players they have access to (this is obvious, but I want to highlight one potential cause for the disparity in the graph above). The following graphs show the average minutes played per regular season by all draft picks per team for the first two rounds of the draft. The graphs are sorted left to right in terms of the teams with the highest average pick over the last five years.
A few quick observations on the graph for the first round: Don't trust Vancouver with first round picks. They have the highest average pick placement out of any team in the first round, but have the fifth worst contributions from those picks. That's abysmal. San Jose, Montreal, and Seattle are all clustered in the middle by average pick placement, but each team got less than 400 minutes per season from their average first round picks. Again, not great. On the flip side, both Chicago and Colorado have done very well with their first round picks even though they tend to be in the second half of the first round. Chicago's two big first round picks have been Jalil Anibaba (now a Sounder!) and Austin Berry.
A few quick observations on the graph for the second round: Vancouver does much better with second round picks, which makes sense because they also average the highest pick placement for the second round. DC United also does well here with middle of the pack selection. The Galaxy also get great value from the second round even though they tend to pick toward the end of the round. The Sounders are, once again, shown to have a poor track record of picking draftees who make an impact in the regular season. The Timbers, meanwhile, have never had a second round pick play a minute of regular season time. So, Sounders fans, it could be worse.
Overall, there are a few things to point out about these previous three graphs. The first thing is that picking early most of the time helps teams find players that will start or earn a significant amount of minutes during the regular season. Another thing to note is that DC United does a good job of getting guys that can make an impact (or they are just bad which makes it easier for draft picks to start, which keeps them bad, but I digress). The final point I would highlight is the strength of the Galaxy's scouting pool and Bruce Arena's willingness to play people who are drafted, even on a team as good as a the Galaxy.
My last two graphs highlight the overall drafting abilities of teams, without regard to draft position or strength of squad. The first graph shows an average of the number of minutes played per season by draft picks, but only takes into account players who earned at least one minutes of regular season playing time in MLS. As you can see, Portland draft picks tend to make significant contributions on a per season basis when they can actually make the team and get minutes. However, as you'll note in the second graph, Portland drops to 14th when considering all draft picks, which means the vast majority of their picks play no regular season minutes.
For the Sounders, the story doesn't get any better. They're second to last in both graphs, which means their draftees make very little impact on the regular season no matter how you look at the numbers. The fact that Zakuani got hurt and Andy Rose isn't included definitely lowers the numbers for the Sounders, but no matter how you look at the data it's not a great sight for youth development through the draft. I think this would probably change if I had data for the Open Cup and CCL, but this is all I have for now. There's also still plenty of time for guys from the past few years to blossom, which I hope to see from Zavaleta especially.
All in all, not great news for the Sounders. Hopefully they can reverse their fortunes tomorrow and pick up some solid depth pieces that can contribute to an outstanding season. Thanks for taking the time to read all this, and please let me know if you have any questions. I'm happy to review the data and do more cuts as people request them.