Jalen Ramsey to have knee surgery, miss start of season.
ACL is intact, but surgery may lead to "few months" absence.
Dolphins struggle with cornerback injuries over the years.
Second-year CB Kader Kohou may step up in Ramsey's absence.
GM Chris Grier highlights the importance of cornerback depth.
Dolphins face tough opponents in first 11 weeks of season.
Kohou eager to learn from Ramsey's addition to the team.
Xavien Howard, Dolphins CB, confident in his abilities.
Dolphins have fourth-toughest schedule in the NFL.