Kobe Bryant has decided to retire after this season, ending his 20-year career with the Los Angeles Lakers.

The 37-year-old Bryant made the announcement in a post on The Players' Tribune on Sunday. The third-leading scorer in NBA history wrote a poem entitled Dear Basketball to announce his decision.

"My heart can take the pounding. My mind can handle the grind. But my body knows it's time to say goodbye," Bryant wrote. "And that's OK. I'm ready to let you go. I want you to know now. So we both can savor every moment we have left together. The good and the bad. We have given each other all that we have."

Bryant went straight from high school in suburban Philadelphia to the Lakers in 1996, and he earned five championship rings and 17 All-Star selections during two decades with the franchise - the longest tenure with one team in NBA history. Bryant also won two Olympic gold medals.

But Bryant's past three seasons have ended early due to injuries, and he played in only 41 games over the previous two years. He has struggled mightily in the first 15 games of this season with mostly young teammates on a rebuilding roster, making a career-worst 32 percent of his shots and dealing with pain and exhaustion every day.

The Lakers (2-13) hosted the Indiana Pacers on Sunday night, and fans arriving at Staples Center received a letter from Bryant in a black envelope embossed with gold.

"I had to just accept the fact that I don't want to do this anymore, and I'm OK with that," the dry-eyed, smiling Bryant said after the game. Bryant scored 13 points on 4-of-20 shooting as the Pacers hung on to send LA to its sixth consecutive defeat, 107-103.

"Kobe was my Jordan," said Southern California native Paul George, who scored 39 points for Indiana to beat the Lakers after Bryant missed a late 3-pointer to tie it. "Watching him win championships when I was growing up, that's who I idolized. That was the standard."

In recent months, Bryant repeatedly said he did not know whether he would play another season, clearly hoping for a rebound in his health and the Lakers' fortunes.

Neither has happened, and the ever-impatient Bryant did not wait any longer to decide his future.

"Kobe Bryant is one of the greatest players in the history of our game," NBA commissioner Adam Silver said.

"Whether competing in the Finals or hoisting jump shots after midnight in an empty gym, Kobe has an unconditional love for the game.

"I join Kobe's millions of fans around the world in congratulating him on an outstanding NBA career and thank him for so many thrilling memories."

Even during his late-career struggles, Bryant's fans have remained devoted to the 6-foot-6 star who won titles alongside Shaquille O'Neal in 2000, 2001 and 2002 before teaming with Pau Gasol for two more in 2009 and 2010.

Only 13 players in league history played on more championship teams than Bryant.

Even with the Lakers already likely to miss the playoffs for the third straight season - a first in franchise history - Bryant intends to keep going. He decided to suit up against the Pacers on Sunday even after playing 34 minutes in Portland the previous night.

"He kind of shocked me when he told me," said Lakers coach Byron Scott, Bryant's teammate during the 1996-97 season. "I'm just sad, more than anything. He's somebody I truly care about and have a lot of respect for. I thought he probably had at least another year. We've still got a lot of games left, so I know his purpose is to finish the season."

Bryant is the NBA's highest-paid player this season with a $25 million salary bestowed on him by grateful Lakers owner Jim Buss.

Bryant has been tirelessly devoted to the franchise, repeatedly declaring he would never play for another NBA team in his final seasons despite the Lakers' wholesale rebuilding following the disastrous 2012-13 campaign.

Bryant has stated that he did not want a farewell tour in the style of Kareem Abdul-Jabbar or Derek Jeter, his friend and founder of The Players' Tribune. But the Lakers' eight-game road trip beginning next week is almost certain to begin a prolonged goodbye to one of the NBA's most popular and most divisive players.

"It's tough to see one of the absolute greatest competitors go through this," Miami guard Dwyane Wade said on Sunday.

"You can put a team around a guy to help a guy, especially late in his career. The Lakers are just not in position right now to do that. He's won five championships, so no one feels bad for him from that standpoint. But from a standpoint of seeing one of this era's greatest players go out in a rebuilding process, it's tough."

The Lakers' next road game is in Philadelphia on Tuesday - perhaps not coincidentally, given the strange timing of Bryant's announcement.

"Philly is where I grew up," Bryant said earlier this month. "It's always a different emotion there than anywhere else."

Bryant was the first guard ever to be drafted directly out of high school, taken 13th overall by the Charlotte Hornets and traded to the Lakers.

Although he won the dunk contest at the All-Star Weekend as a rookie, his Lakers didn't become title contenders until coach Phil Jackson arrived in 1999.

Bryant made a fourth NBA Finals appearance in 2004 despite his preseason arrest for sexual assault and subsequent legal proceedings that often required him to fly from Colorado to Los Angeles on game days.

The assault case was dropped in September 2004, but his behavior affected his reputation.

Bryant scored 81 points against Toronto on Jan 22, 2006, the second highest-scoring performance in NBA history behind Wilt Chamberlain's 100-point game.