Calvin Johnson had informed the Detroit Lions he plans on retiring. 

Johnson has been one of the NFL's best receivers throughout his career. 

Johnson told friends and family before last season that 2015 would be his final year in the NFL. 

Calvin Johnson has no timetable for when he will make a decision about whether he will play in the 2016 season.

Johnson alluded to possibly retiring after the Detroit Lions' last game of the season.

Johnson is now 30 years old and has slowed down from his historical 2012 season in which he caught 122 balls for 1,964 yards.

Johnson caught 88 balls for 1,214 yards and nine touchdowns in 2015.

The Detroit Lions have retained Jim Caldwell as head coach.

"After spending a significant amount of time together, it is clear that our football philosophies are very similar," new general manager Bob Quinn said Friday. "Consequently, I am convinced he is the right man to lead our football team moving forward.

"Jim's entire body of work is impressive. Not only did he lead the Lions to the playoffs his first season here, but when you look at how the players responded the second half of last season, under difficult circumstances, it's clear to me that this team believes in him and responds positively to his leadership."

Caldwell was hired by the Lions in January 2014 and immediately turned around the struggling franchise, going 11-5 in his first season. 

The Detroit Lions have hired Bob Quinn as general manager.

Quinn has spent his entire career with the New England Patriots.

Quinn was most recently the Patriots' director of pro scouting.

Calvin Johnson admitted he's evaluating his future and whether it might be time for a change of scenery.

Johnson has four seasons remaining on his seven-year contract. His base salary for next season is $15.95 million. Johnson's contract carries a cap hit of $24 million for the Detroit Lions next season.

"Like many players at this stage of their career, I am currently evaluating options for my future," the 30-year-old Johnson said in the statement. "I would expect to have a decision regarding this matter in the not-too-distant future."

Johnson said he's not sure what the future holds after the Lions' final game of the season.

"We obviously have profound respect for Calvin," the Lions said in a statement. "And certainly understand and appreciate his decision to give proper thought and consideration to his football future."

Johnson reportedly cleaned out his locker unlike other veteran players.

Johnson also told his mother he's not sure if he wants to keep playing.

The Seattle Seahawks finished the 2015 season ranked first in Football Outsiders' Total DVOA following their blowout victory of the Arizona Cardinals.

The Seahawks have now finished first in DVOA for four straight seasons, which is the first time the feat has been accomplished.

The Cincinnati Bengals rank second in Total DVOA ahead of the Cardinals, Carolina Panthers and Kansas City Chiefs.

These were also the five teams, the Seahawks, Bengals, Cardinals, Panthers and Chiefs, to finish the 2015 regular season in the top-10 in both Offensive and Defensive DVOA.

Adam Gase, Ben McAdoo and Teryl Austin are candidates for the Philadelphia Eagles' head coaching vacancy.

Gase spent this past season as offensive coordinator of the Chicago Bears and was a coveted head coaching candidate last offseason.

McAdoo has been the offensive coordinator of the New York Giants for the past two seasons.

Austin has been the Detroit Lions' defensive coordinator over the past two seasons.