Where Would the Nats be Without Gio
This past off-season Gio Gonzalez could have easily ended up on the Red Sox. What if the Nationals felt that AJ Cole was too good of a prospect to deal to the A's for Gio and the Red Sox had ended up out bidding the Nationals? Gio Gonzalez has arguably been the best pitcher on the Nats staff with a 3.13 ERA over 118 innings and a 10.14 K/9 rate. Gio has been a masterful pitcher and has amassed 3.4 WAR while doing so, but so where would the Nats be without him.
The first thing to do is to imagine that the trade never happened. That the Nats felt the price were too high and went with what they had. Tommy Milone, John Lannan, and Brad Peacock were left to fight it out for the final spot in the Nationals rotation. Now to make this argument easier assume Tommy Milone is the one who makes the Nats rotation and his 1.1 WAR is the same in Washington as it is in Oakland ignoring the fact that he has a 5.69 ERA on the road to only a 0.91 ERA at home.
The big gain for the Nationals from not trading for Gonzalez wouldn't be Milone it would be Derek Norris. There is no way the Nationals could have predicted what would have happened with their catching situation, but it is also hard to not think about how much Norris would be helping the team right now. Both Flores and Norris have a 0.2 WAR, but Flores has needed 61 games to reach that level while Norris has needed 19. Making Norris' WAR per game 0.01 which over the 61 games Flores has played for the Nationals would be 0.6 or 0.4 wins better than Flores.
If the Nats hadn't had traded for Gio Gonzalez then their net loss in wins this season would be 1.9 or almost two entire wins which could make a huge difference down the stretch. They would also still have Peacock and Cole in the minor leagues but both of them have struggled this season and one of the first things the Nationals did when they acquired Gio was to lock him up long term. That deal and the trade now look like a major win for the Nationals not just for the short term, but for the long term as well.