The New England Patriots had three major needs as they marched into free agency and the draft: 1) cornerback; 2) defensive line; 3) offensive line.
They've used both the draft and free agency to address the trenches. On defense, they've added Jabaal Sheard, in addition to three top draft picks on Malcom Brown, Trey Flowers, and Geneo Grissom. On offense, they used two fourth round picks on Tre Jackson and Shaq Mason to be long term fixes for the offensive line. Jackson and Mason were the 2nd and 4th highest draft picks Bill Belichick has ever used on a player who aligned on the interior in college (Bryan Stork is 1st, Rich Ohrnberger is 3rd).
At cornerback? They signed Bradley Fletcher, who has the ignominy of having allowed the most passing yards of any cornerback in the league in Pro Football Focus' history (back to 2008). They added Robert McClain, who was a spot starter in his past three seasons with the Falcons. They also released Alfonzo Dennard and Kyle Arrington, which most Patriots fans would interpret as a net negative.
The reality of the roster leaves the cornerback position as the only one with major questions. Others have uncertainty- which two of Jackson, Mason, and Wendell will start at guard? Can James White beat out Travaris Cadet to be the receiving back?- but at least the bodies are on the roster.
With cornerback, it's unclear who will make the roster. Yes, Logan Ryan and Malcolm Butler are the closest things to locks, along with Bradley Fletcher. Beyond those players, most would have said Kyle Arrington was the next in line. If Robert McClain is presumed to be the new slot corner, that leaves Justin Green or Chimdi Chekwa as the fifth corner on the roster. Perhaps rookie seventh round pick Darryl Roberts can surprise, or camp favorite Daxton Swanson can leave another positive impression.
The whole cornerback position is shrouded in mystery and won't be revealed until final cuts are handed in before the season. The Patriots did a good job of addressing most of its roster holes during the off-season, but it seems most likely that New England will have to add another player to the cornerback competition before camp concludes.