At least according to the fine folks over at Fangraphs in this article. Of course there are a few qualifiers and is only looking at 2013 performances, with 14 teams not having middle infield combinations that meet the requirements.
Either way it is a great article and a good sign for the Padres as they have team control over both players (2017 for Everth, 2019 for Jedd the great) for a good amount of time. Basically given that Jedd hasn't been horrible with the glove and has made up for his slow start in April (and he is trending defensively to 'meh'), and Everth's change of approach at the plate dramatically cutting down on his K%, the combo has the has the highest WAR for those they (FanGraphs) felt qualified. They are also the youngest combo on the list.