Haden underwent surgery on his left ankle Wednesday, the team said. The injury occurred in Week 8 against the Arizona Cardinals.
The Browns have to hope Haden can meet the timetable. The secondary struggled without him last season and the Browns already have lost former Pro Bowl free safety Tashaun Gipson to free agency.
The team's depth at cornerback is also iffy.
Tramon Williams is the other starter, but his forte is not man coverage. In Haden's absence, Pierre Desir started six games last year, Charles Gaines four and Justin Gilbert one. Gilbert has been a large disappointment since he was taken eighth overall in the 2014 draft.
He is expected to resume football activities sometime during training camp, with the expectation that he will be ready by Week 1 of this upcoming season, the team said.
Haden, who turns 27 next month, played in just five games last season as numerous injuries (concussion, rib, finger, ankle) kept him inactive for most of the season. He was placed on season-ending injured reserve on Dec. 14, the result of a concussion he also sustained against Arizona.
He was cleared from the concussion protocol on Jan. 12.
Haden, a two-time Pro Bowl selection, has started 69 of the 77 games he has played for the Browns since the team selected him seventh overall in the 2010 draft. He has 16 career interceptions.
Information from ESPN's Pat McManamon was used in this report.