Anquan Boldin never quite got the respect he deserved

The NFL and its fans never got the chance to say a proper goodbye to receiver Anquan Boldin, as the 14-year veteran announced Sunday that he's hanging up his pads to focus on humanitarian work.

While Boldin had every right to decide when his football career was over, the 36-year-old's surprise departure came before the football world could truly extend its collective appreciation for a player of his accomplishments and sacrifice.

Boldin had a chip on his shoulder ever since entering the league with the Arizona Cardinals in 2003 - a playing style that set the tone for the rest of his career. Here's a look at what made him so great:

Red-hot start

No receiver has ever begun their career like Boldin. On Sept. 7, 2003, the Detroit Lions became the first team to find out what the second-round pick was all about as he racked up 217 yards on 10 catches with two touchdowns against them, setting a record for the most receiving yards in a debut game.

The Florida State product continued his torrid start by setting a rookie record for receptions in a season with 101 while piling up 1,377 yards and eight touchdowns. His team-leading campaign was enough to win the 2003 NFL Offensive Rookie of the Year Award, and he didn't stop there.

Career accomplishments

Boldin kept up his rookie pace throughout the early years of his career, as he went on to set records for the fastest player to reach 200, 300, 400, and 500 receptions by the end of his sixth season. He made three Pro Bowls between 2003 and 2008, but undeservedly never made it back to the All-Star festivities again.

As Boldin moved from Arizona to the Baltimore Ravens ahead of the 2010 season, he brought a level of toughness and consistency that meshed perfectly with the team's identity. In 2012, he led the Ravens in receiving and played a major role in their run to a Super Bowl title.

Throughout Boldin's career, he steadily accumulated stats year in and year out, eventually landing near the top of every major category while never quite receiving the attention paid to other stars. He sits ninth all time in receptions (1,076), 14th in receiving yards (13,779), and 23rd in touchdowns (82). Hypothetically, if Boldin had produced a modest season in 2017 - with at least 27 catches, 567 yards, and seven touchdowns - he would have been fourth all time in catches, 10th in yards, and 13th in touchdowns.

Off-field contributions

As much as he's done on the field, Boldin's contributions off it may be the most important part of his legacy, as reflected by his recent decision to focus on human rights over football.

Boldin started the Q81 Foundation in 2004 during his sophomore campaign. His charity has been "dedicated to expanding the educational and life opportunities of underprivileged children," which includes a summer enrichment program, a scholarship fund, holiday shopping sprees, thanksgiving dinners, and an annual event in Florida. He also went with former teammate Larry Fitzgerald to Ethiopia in 2012 to help create farmable land, and visited congress with fellow NFLers this spring to discuss police and community relations.

Related: Boldin, 3 other NFLers write op-ed pushing for U.S. criminal justice reform

In 2015, Boldin was honored by the NFL and his peers with the Walter Payton Man of the Year Award for his community service.

Different places, same face (mostly)

One of the biggest reasons that Boldin's success was difficult to appreciate for fans is that he moved around the league a bit. With five teams on his resume, Boldin made each stop shorter than the last, but his effort never dipped.

Whether it was Josh McCown, Kurt Warner, Matt Leinart, Joe Flacco, Colin Kaepernick, or Matt Stafford throwing him the ball, Boldin gave his all in whatever role the team asked of him. He was toughness personified, never afraid to take a hit to make a play, even breaking his face in 2008 and returning three weeks later.

Boldin's three Pro Bowl appearances, all coming in the first six seasons of his 14-year career, don't do justice to one of the most consistent receivers and respected players the NFL has seen over the last decade and a half.