Tuesday marks the first day for NFL teams to place the franchise or transition tag on players, one of many important dates on offseason calendar between now and the start of training camp.

Seahawks coach Pete Carroll and general manager John Schneider have both said they like the team they have and that they hope to keep it together as much as possible, but they both also understand that some change is inevitable in the NFL, and that a lot of important decisions between now and this summer will go into shaping the 2016 roster.

"We're a darn good football team," Schneider said on 710 ESPN Seattle last month. "We love our players. We have 17 unrestricted free agents coming up, and we're excited for the challenge of keeping this really cool puzzle together.

"We attack the offseason. We're going to attack it the same way we always have. Obviously we know what our deficiencies are, and we're going to try to compensate for those deficiencies as we go, but we're not going to crazy in one area and panic just because we think we're struggling there. We're going to be smart, we're going to be aggressive."

Here are some of the key offseason dates for the Seahawks and the rest of the NFL:

Feb. 16: First day for clubs to designate Franchise or Transition Players. The Seahawks have used these tags only once under Carroll and Schneider, placing the franchise tag on kicker Olindo Mare in 2010.

Feb. 23-29: NFL Scouting Combine, Lucas Oil Stadium, Indianapolis.

March 1: Deadline for clubs to designate Franchise or Transition Players at 1 p.m. PT.

March 7-9: Clubs are permitted to contact and enter into contract negotiations with the certified agents of players who will become Unrestricted Free Agents upon the expiration of their 2015 Player Contracts at 1 p.m., PT, on March 9. However, a contract cannot be executed with a new club until 1 p.m., PT, on March 9.

March 9: 2016 NFL League Year begins. Free agency opens at 1 p.m. PT.

Prior to 1 p.m. PT, clubs must exercise options for 2016 on all players who have option clauses in their 2015 contracts.

Prior to 1 p.m. PT, clubs must submit qualifying offers to their Restricted Free Agents with expiring contracts and to whom they desire to retain a Right of First Refusal/Compensation.

March 20-23: Annual League Meeting, Boca Raton, Florida.

April 4: This doesn't apply to the Seahawks, but clubs that hired a new head coach after the end of the 2015 regular season may begin offseason workout programs.

April 18: Clubs with returning head coaches, including Seattle, may begin offseason workout programs.

April 22: Deadline for Restricted Free Agents to sign Offer Sheets.

April 28-30: 2016 NFL Draft, Chicago, Illinois.

After the final selection in the Draft has been made, clubs may begin signing Undrafted Free Agents who were eligible for the 2016 Draft.

May 6-9 or May 13-16: Teams may elect to hold their one three-day post-draft rookie minicamp from Friday through Sunday or Saturday through Monday of the first or second weekend after the NFL draft.

May 20-23: NFLPA Rookie Premiere. Invited Rookies (typically, first and/or second-round selections) must be permitted by their respective clubs to attend. Such players are unavailable for offseason workouts, OTA days, and minicamps during this period.

May 23-25: NFL Spring League Meeting, Charlotte, North Carolina.

June 1: Deadline for prior club to send "June 1 Tender" to its unsigned Restricted Free Agents who received a qualifying offer for a Right of First Refusal Only in order for such player to be subject to the CBA's "June 15 Tender" provision.

For any player removed from the club's roster or whose contract is assigned via waivers or trade on or after June 2, any unamortized signing bonus amounts for future years will be included fully in Team Salary at the start of the 2017 League Year.

June 19-25: Rookie Symposium, Aurora, Ohio.

July 15: At 1 p.m. PT, deadline for any club that designated a Franchise Player to sign such player to a multiyear contract or extension. After this date, the player may sign only a one-year contract with his prior club for the 2016 season, and such contract cannot be extended until after the club's last regular season game.

Mid-July: Training camps open. Clubs are permitted to open preseason training camp for rookies and first-year players beginning seven days prior to the club's earliest permissible mandatory reporting date for veteran players. Veteran players (defined as a player with at least one pension-credited season) other than quarterbacks or injured players may report to a club's preseason training camp no earlier than 15 days prior to the club's first scheduled preseason game or July 15, whichever is later.

August 7: The annual Hall of Fame game takes place in Canton, Ohio, kicking off the NFL preseason. This year's game will be between the Indianapolis Colts and Green Bay Packers.

September 8: The NFL regular season begins with a Thursday night game, which traditionally is hosted by the defending Super Bowl champions. The rest of the NFL will begin regular-season play on Sunday, September 11 or Monday, September 12.