New England's slot cornerback is a position in question

Last year, CB Logan Ryan led the Patriots in snaps in slot coverage with 309. The next closest among cornerbacks was Malcolm Butler at 82, though safety Patrick Chung did log 147.
Heading into the 2017 season, New England’s top three corners, Malcolm Butler, Stephon Gilmore and Eric Rowe combined for 136 snaps in slot coverage last season.
The Patriots will need someone to step up into that slot role with Ryan gone. Butler is one possible candidate, as it would allow New England to keep the taller Rowe and Gilmore on the outside. Butler is an extremely productive cornerback – his 88.6 overall grade in 2016 ranked seventh at the position – but he’s allowed a 128.5 passer rating to opposing quarterbacks when lined up in the slot on 225 coverage snaps over the past two seasons.
Justin Coleman is another potential candidate to fill that role, even though he only played 43 snaps in slot coverage last season, he only allowed a 39.6 passer rating, tied for 10th best among all players in the NFL at the position.
The likely scenario is that the Patriots rotate defenders in and out, which will call for safety Patrick Chung to continue his strong slot play, as last year he only allowed a passer rating of 87.8 when targeted while covering the slot.