The Patriots quietly need to add to their cornerbacks on the roster because there are a lot of question marks.

Can Malcolm Butler continue his ascent to the top of the league? (Hopefully).

Will Logan Ryan be gone after the 2016 season? (Possibly).

Does Darryl Roberts even make the team after being a 2015 7th round pick? (It's not a lock).

Is Rashaan Melvin really the only other cornerback under contract? (Yep).

Sure, rising sophomore Justin Coleman will likely be extended a new contract, but the point is that this positional grouping is far from perfect. Butler is the only player that will most probably be around beyond 2016, and the Patriots don't like to be caught unprepared.

Just remember, if either of Butler or Ryan went down last season, that secondary would've been a disaster. The depth at the position wasn't great and that has to be fixed moving forward. The team would be smart to add a veteran to stabilize the youth, and possibly even bring in another quality draft pick.

Here's a list of possible free agents.

6. Vikings CB Josh Robinson; 25 years old. Robinson lost his starting role to a pair of first round picks and a veteran from the new head coach's old team. He's tremendously athletic and he could be looking for a one-year prove it deal with a team to help his contract value moving forward. He could find a $2 million per year deal, similar to the #5 player on this list did last season.

5. Chargers CB Patrick Robinson; 26 years old. Robinson played well in his one year with the Chargers and could probably serve as a quality #2 or #3 corner for most teams around the league. He'll likely pick up a multi-year contract for $3 million or so per season, depending on how much the new team trusts in his ability. He's still very young.

4. Chiefs CB Sean Smith; 29 years old. Smith would be an incredible fit in the Patriots defense, but will probably command upwards of $8 or $9 million per year on the open market. While that might be too expensive for the Patriots taste, if they could make it work, he and Butler would lock down the New England secondary for the next three years.

3. Patriots CB Tarell Brown; 31 years old. Brown wants to be back and he played well to start off the year. Why not invite him back to camp, just in case any of Roberts, Coleman, Melvin, or a draft pick don't pan out? He'll be around for cheap, too, and would probably match his prior contract at roughly $2 million per season.

2. Packers CB Casey Hayward; 26 years old. Hayward is in a similar boat to Josh Robinson in that the Packers have invested heavily in a young secondary and he'll be an odd-man out. Hayward is a great slot corner with ability on the outside; he's a boost over Logan Ryan. He'll probably command between $5 and $6 million per year on the market.

1. Rams CB Trumaine Johnson; 26 years old. Overshadowed by his partner Janoris Jenkins, Johnson really emerged as a quality cornerback in 2015. He's hitting the market at the perfect time and could probably fetch a similar contract to Hayward. The question is whether that's too expensive for the Patriots.