Key NFL dates on 2013 calendar

A look at key dates on the 2013 NFL calendar:

Feb. 20-26 -- NFL Combine (Indianapolis)

March 9-11 -- Clubs can begin negotiations with certified agents for players who are free agents

March 12 -- Free agency begins at 4 p.m. ET (all clubs must be under salary cap w/ top 51 players)

March 17-20 -- Annual league meeting (Arizona)

April 25-27 -- NFL Draft (1st round on 25th; 2nd-3rd rounds on 26th; 4th-7th rounds on 27th)

May 20-22 -- NFL spring meeting (Boston)

Late July -- Start of Patriots training camp

Sept. 5 -- NFL Kickoff Game (at Baltimore)