Every winter, baseball fans go nuts with free agency talk. Fans of good teams look forward to adding "that last piece" while the poor teams look to get better. While the fanfare surrounding the amateur draft and July 2nd signing period has increased over the years, the instant results of free agency and trades hold a death grip on most people's excitement level. After all, they're just prospects. Give me someone proven, someone with experience, someone good.
Well, in that case, you may want to pay attention to the amateur talent. Using FanGraphs' WAR leaderboard, I took the top 35 hitters and top 35 pitchers and figured out how each was acquired by their current team. Categorizing them by amateur talent, trade (as a minor or major leaguer), and free agency signing. I'm guessing the results are going to shock very few of the people who frequent this site, but would be met with some scratched heads by the spreaders of common knowledge.
39 of the 70 were acquired as amateur talents. 18 via trade and the rest, all 13 of them, were signed as free agents. Some, like Russell Branyan and Marco Scutaro, were low-budget signings that morphed into inflaming pieces of awesome. In percentage form, 55% are still on their first team and about 19% signed a free agent contract. That separation is pretty decent. That's not to say every big free agent signing has resulted in a bust. Raul Ibanez, Mark Teixeira, and CC Sabathia are all amongst the 70.
Not every trade was for a proven veteran either, teams took chances on players like Ben Zobrist, Freddy Sanchez, and Chone Figgins while others traded for Scott Rolen, Miguel Cabrera, and Dan Haren. There's a bit of a selection bias here as well, since each team drafts 50 players a year, and signs only handful or two of free agents.
General Managers may win over the public's perception by doing signing free agents, but teams aren't getting star performances from them. Drafting and trading well, that's where teams are finding the big talent.