Feb 3: Waiver system begins with a 24-hour claiming period and runs through the Friday prior to the last game of the regular season. Vested veterans (those with four or more accrued seasons) are not subject to waivers until after the trade deadline.
Feb 8-9, 15-16, 22, Mar 1, 8-9, 15, 22-23, 29-30: Regional Combines
Feb 17: Teams have from this date until 4pm ET on Mar 3 to designate a franchise or transition player (unlikely for Denver)
Feb 19-25: National Scouting Combine in Indianapolis
Mar 3: Peyton Manning will undergo a neck exam to determine his future availability.
Mar 8-11: Teams may negotiate with their own pending UFAs until 4pm ET on Mar 11, when the league year begins. Contracts may not be finalized until after that deadline. Denver's unrestricted free agents are: Eric Decker, Dominique Rodgers-Cromartie, Zane Beadles, Knowshon Moreno, Robert Ayers, Wesley Woodyard, Shaun Phillips, Mike Adams, Stewart Bradley, Quentin Jammer, Andre Caldwell, Paris Lenon, Jeremy Mincey, Winston Justice, Michael Huff, Steve Vallos, Marquice Cole, and Dan Koppen.
Mar 11: Prior to 4pm, teams must exercise all option clauses and submit qualifying offers to pending RFAs (Restricted Free Agents) and ERFAs (Exclusive Rights Free Agents). According to OTC, Denver's RFAs are Chris Harris, Mitch Unrein, and Trindon Holliday, while their ERFAs are Tony Carter, Duke Ihenacho, and Brandon Marshall. Spotrac lists Holliday as an ERFA, and Marshall as an RFA.
At 4pm, all 2013 contracts expire, and teams must be under the salary cap under the Top 51 rule, when only the top 51 cap figures on the roster count toward the overall team figure. This rule is important since roster limits expand to 90 during the offseason.
The 2014 League Year, free agency, and trading period commence at 4pm ET.
Mar 23-26: Annual League Meetings in Orlando, FL
Apr 12-13: Super Regional Combine in Detroit, MI
Apr 21: As a team with an incumbent head coach, Denver's offseason workout program may begin.
May 2: Deadline for RFAs to sign offer sheets, which almost never happens in today's NFL.
May 2: Deadline for teams to match RFA offer sheets.
May 8-10: 2014 NFL Draft
May 19-21: League Spring Meeting in Atlanta, GA
Jun 22-28: Rookie Symposium in Aurora, OH
Jul 15: 4pm ET deadling to sign franchise tagged players to multi-year deals
Updated 2/4/14 5:15pm ET - Added Jeremy Mincey and Marquice Cole to list of pending UFAs, as per DP