I have Insider, and to answer your original question: The article is just about how Football Outsiders expects a few players, including Lee Evans, to increase their "YAC Plus" statistic this year, while they expect a few other players, including Miles Austin, to decline in this category.
"YAC Plus" is essentially how many yards MORE than the typical YAC a player gets for a specific pass reception scenario (so if an 8 yard pass to the left typically results in a YAC of 3, and Lee Evans got 4 yards, then he'd have a YAC Plus of 1). They average your YAC Plus for every reception and compare to other players. They expect Lee's to rise and Austin's to fall.