Gasol started his career with Barca in the 1998-99 season before entering the NBA draft three years later, selected third overall by the Atlanta Hawks.
A storied stay in the United States followed, notably taking in a six-year stretch with the Los Angeles Lakers.
But Gasol has not played in the NBA since March 2019 due to a foot injury and was waived by the Trail Blazers later that year without playing a single game in Portland.
The center, now 40, has continued to discuss a potential return to action, with the suggestion of a move back to the Lakers mooted when Marc Gasol, his brother, signed for the team this season.
However, the idea of turning out for the Blaugrana once again had also appealed to Barcelona-born Gasol.
Responding to the reported move last week, Gasol wrote on Twitter: "I remain focused on my recovery and I am not ready to get back to competing just yet."
But he added he would announce any future news on his social media account, and Gasol had an update on Tuesday.
"I'm very happy to announce that I'm coming home and that I'll soon join the ranks of Barca's basketball team," Gasol said.
"I want to put my skills and experience at the disposal of the club at a key point in the season, while at the same time making progress in my physical condition and getting into the rhythm of competition.
"I'm happy to return to the club where I began, and I'm excited about this new opportunity: I hope to contribute to the first team very soon. I want to thank Barca and its technical staff for making it possible to join them."
Barcelona announced he has joined until June 30, stating on their website: "FC Barcelona is delighted that Gasol has decided to sign and return to the place that has always been his home. The club is pleased and honoured that Pau will be wearing the blaugrana colours once again."
The upcoming Olympic Games would appear to be a motivating factor in a move that seemingly ends the six-time All-Star's NBA career.
Gasol, the Rookie of the Year winner in his debut season with the Memphis Grizzlies, played 1,226 regular season games in the NBA, averaging 17.0 points, 9.2 rebounds, 3.2 assists, 1.6 blocks and 0.5 steals.
His best scoring season brought 20.8 points per game in 2006-07, his final full campaign with the Grizzlies, although he was an increased threat on the boards later in his career, with 11.8 rebounds per game with the Chicago Bulls in 2014-15.
Between starring for Memphis and Chicago, Gasol joined Kobe Bryant on two title-winning teams in LA, although he first lost in the Finals shortly after joining the Lakers in 2008.
Gasol started all 46 playoff games across their successes in 2008-09 and 2009-10, having been named to the All-NBA Third Team in the regular season on each occasion.
The Lakers star then made the Second Team with 18.8 points and 10.2 rebounds per game the following year.
Gasol, who retired from the NBA following the 2018-19 campaign, spent seven of his 18 seasons with the Lakers after being acquired from the Memphis Grizzlies in a trade at the 2008 deadline.
Having been named the 2002 Rookie of the Year, the seven-foot Spaniard made his first All-Star team in 2006 after averaging 20.4 points, 8.9 rebounds and 4.6 assists per game, but he would not make another until arriving in LA.
After Gasol's arrival, the Lakers went from a first-round exit in 2007 all the way to the NBA Finals, falling short against historic rivals the Boston Celtics in six games.
With a training camp under their belt and in his first full season alongside Kobe Bryant, Gasol helped the Lakers win their 15th championship, and Bryant's fourth. He averaged 40.5 minutes and shot 58 per cent from the field for his 18.3 points and 10.8 rebounds in 23 playoff games.
The Lakers then went back-to-back in the 2009-10 season, when Gasol was the most valuable player on the floor during their Game 7 victory against the Celtics, finishing with 19 points, 18 rebounds and two blocks in a game where Bryant had 23 points and 15 rebounds, but shot six-of-24 from the field.
He was named an All-Star in both championship seasons, and again in 2010-11, and then spent three more years with the Lakers until heading to the Chicago Bulls, where he would make two more All-Star Games.
Prior to the ceremony, Gasol spoke to the media about the honour of having his number go up in the rafters alongside Bryant.
"I think I’ve done as good as I could to really embrace it and savour it, but tonight really exceeds any dream or expectation that I’ve had," he said. "Obviously with Kobe up there, it just adds something meaningful, and powerful, and sad, and happy, and painful, and joyful. It’s a lot of things.
"The excitement, the anticipation, the honour received, it’s just so big that it's been hard to really take it in.
"I have to keep reminding myself that it’s a celebration. It's great. It's lovely. It's just great that you can experience this in your life."
Gasol was also an incredibly decorated international competitor, finishing as the highest scoring player at the 2004 Olympics, before guiding Spain to their first ever FIBA World Championship in 2006, where he was named the tournament's Most Valuable Player.
He is also the all-time leading scorer in EuroBasket competition, overtaking Dirk Nowitzki and Tony Parker with 1,183 points scored in 58 games at an average of 20.4.
A ceremony will take place on March 7, 2023 when the Lakers host the Memphis Grizzlies.
Gasol played for the Lakers between 2008 and 2014, having arrived from Memphis, appearing in three NBA Finals and winning two championships alongside Kobe Bryant.
Three of his six All-Star appearances came during his time in Los Angeles, before he left for the Chicago Bulls in 2014.
After time with the San Antonio Spurs and Milwaukee Bucks, Gasol returned to Europe for a second spell with Barcelona, where his career had begun, before retiring in October last year at the age of 41.
Following the announcement, Gasol took to Twitter to thank his former franchise, writing: "Beyond thankful and honoured!!!"
Gasol had an average of 17.7 points per game during his time with the Lakers, as well 9.9 rebounds, 3.5 assists and 1.4 blocks in 429 appearances.
He will join a number of legends, including Kareem Abdul-Jabbar, Shaquille O'Neal, Bryant and Magic Johnson, in having his jersey retired by the Lakers.
Legendary coach Popovich has won five NBA titles with the San Antonio Spurs, and is one of a number of people named as a contender in their first year of eligibility.
Popovich is a perhaps surprise inclusion, with it previously unknown when he would qualify to be recommended for the honour.
Other potential inductees include Pau Gasol, Tony Parker and Dwyane Wade, while the 1976 U.S. Olympic women's basketball team also made the list.
The finalists for the class of 2023 will be announced on February 17 during All-Star weekend, before the final nominees are named on April 1 during the NCAA Final Four.
The players will then be enshrined on August 11 in historic Springfield, Massachusetts, where the sport of basketball was invented.
The San Antonio Spurs coach has won five NBA titles and more games than anyone else in the history of the league, with 1,363 regular season victories and a further 170 in the postseason.
Headliners joining Popovich in the class of 2023 are Dirk Nowitzki and Dwyane Wade, as well as two players who played under 'Pop' in San Antonio, Tony Parker and Pau Gasol, and his former assistant and San Antonio Stars player Becky Hammon.
Popovich is coming towards the end of his 27th season with the Spurs, sitting in 14th place in the Western Conference with a record of 19-58.
In better days though, Parker won four championships with Pop at the Spurs, while Gasol makes it more for his success with the Los Angeles Lakers, where he won two titles.
Dallas Mavericks legend Nowitzki won the 2011 championship and is sixth in the NBA's all-time scoring list, while 13-time All Star Wade won three titles during his 13 years with the Miami Heat.
Hammon – a six-time WNBA All Star – worked under Popovich in San Antonio between 2014 and 2022 before becoming head coach of the Las Vegas Aces in the WNBA.
The former Los Angeles Laker, who returned for a second spell with his first club Barcelona eight months ago, confirmed his decision to call time on his illustrious career a press conference on Tuesday.
Gasol enjoyed an extraordinarily successful NBA career spanning 18 years, playing for the Memphis Grizzlies, Los Angeles Lakers, Chicago Bulls, San Antonio Spurs and Milwaukee Bucks.
He won two NBA titles and was a six-time NBA All-Star after being named the 2001-02 NBA Rookie of the Year.
"It is a very difficult decision as you can imagine, but it's a decision that I have contemplated well," Gasol said. "It's nice to be able to retire as an active player and not on crutches, to retire having won another title with Barcelona and having played in a fifth Olympics with the national team.
"I remember when I was on the youth team coaches used to say to that the important thing was not to reach the top, but to stay there. I didn't try to stay there, I tried to improve with every game and become the best I could."
Gasol was FIBA Basketball World Cup champion in 2006, won three FIBA EuroBasket titles - earning the MVP award in 2009 and 2015 - and three Olympic medals (two silver and a bronze).
He is Eurobasket's all-time leading scorer with 1183 points in 58 appearances, averaging 19.9 points in seven tournaments.
"The example that Pau has given us all, that leadership even this last year, with humility, with an ability to try things that he had never even done, things that he did not even need because of his great talent," said Spain head coach Sergio Scariolo. "Another stage of respect and the consideration that we can only have towards Pau."
Gasol and his younger brother Marc, 36, announced their international retirement after playing in the Tokyo Olympics.
Pau Gasol said: "I was lucky to be a member of great teams with great team-mates, and some of them are here today.
"We started playing in the backyard of our grandparents' house and having [Marc] as my brother and playing the same sport, trying to be the big brother also in basketball, was always a great motivation for me.
"I'd like to be remembered as a player who gave it his everything, who tried to do the best he could and, at end of the day, being able to play until the age of 41 is not bad at all."
Wade, Nowitzki, Gasol and Parker are all first-ballot selections after playing their final seasons in 2018-19, while it was also Popovich's first time on the ballot after previously declining Hall of Fame consideration in recent years.
Hammon's elevation was also considered simply a matter of time, with the six-time WNBA All-Star, former long-time San Antonio Spurs assistant and 2022 WNBA championship-winning coach with the Las Vegas Aces having put together a stellar resume since turning pro in 1999.
With Hammon's ties to the Spurs, it figures to be a special night for San Antonio fans as Parker and Popovich are enshrined, joining fellow linchpins of their dynasty Tim Duncan and Manu Ginobili after their inductions in 2020 and 2022 respectively.
Popovich coached the Spurs to all five of their NBA titles – 1999, 2003, 2005, 2007 and 2014 – while Parker contributed to the last four after arriving in 2001 following an impressive youth career in France.
The six-foot-two point guard made six All-Star teams, and was named to the All-NBA Second Team three seasons in a row from 2012-14 as the Spurs battled LeBron James' Miami Heat in a legendary rivalry.
His number nine jersey was retired by the Spurs, as is Nowitzki's number 41 jersey with the Dallas Mavericks.
Nowitzki, who for a long period was European basketball's biggest star, brought the Mavericks their only title in 2011 as he took down the Heat in James' first season there.
The German was named league MVP in 2007, and went on to make 14 All-Star teams, while earning 12 All-NBA selections, including four on the First Team in the space of five years.
While both Popovich and Nowitzki could headline a Hall of Fame class in any given year, that honour may go to Wade, who was the architect of all three of Miami's titles in 2006, 2012 and 2013.
Drafted in 2003, Wade ended up carrying the Heat – alongside Shaquille O'Neal – to their first ever championship in only his third season.
It was the beginning of a run that saw him make 14 All-Star teams, eight All-NBA teams, and three NBA All-Defensive teams as he rivalled James and Kobe Bryant for the status of best player in the league in 2009 and 2010.
While Wade may have been at his peak in 2009 and 2010, both of those seasons ended with Gasol lifting the title with the Los Angeles Lakers.
Gasol spent just six-and-a-half seasons in Los Angeles, but it is where he will be most fondly remembered after making such a profound impact that he recently had his number 16 jersey retired into the rafters alongside running-mate Bryant.
Adding to his NBA resume was his spectacular international play, where he became the all-time leading scorer in EuroBasket play, averaging 20.4 per game in 58 appearances for his country, while also carrying Spain to their first ever FIBA World Cup gold medal in 2006.
