The 20-year-old underwent surgery after suffering the injury in Spain's Euro 2024 qualifying win over Georgia last year.
He subsequently missed the rest of the season, along with Spain's triumph at the Euros.
But Gavi made his return to action on Sunday, coming on as a substitute during Barca's 5-1 win over Sevilla in LaLiga, receiving a standing ovation from the crowd at the Lluis Companys Olympic Stadium.
"I'm very happy to be back with the team. I've been dreaming about this moment for many months and I'm grateful to everyone because they've made it so much easier for me," an emotional Gavi told Movistar Plus.
"The worst thing during the lay-off is not playing with my teammates. Seeing the team from the outside is very hard and gives you a different perspective, you learn that you have to enjoy every moment and appreciate things.
"I feel very lucky to be here today, recovered, because this is my life and what I've been doing all my life and I've missed it a lot.
"When you see all the fans and team-mates over there and they show you that they love you and appreciate you, you feel very lucky."
Hansi Flick added: "For him [Gavi] it was a fantastic moment, a fantastic feeling.
"The result was great. It was a perfect day for him and also for us."
Barcelona are top of LaLiga on 27 points, three ahead of Real Madrid in second and seven clear of Atletico Madrid in third.
They will host Bayern Munich in the Champions League on Wednesday before next weekend's Clasico against Madrid.
"Winning like this is very important for the games to come," Gavi's team-mate Pedri told Movistar Plus.
"Today we had to leave with more than just the three points, we needed that good feeling we got.
"The coach told us that there was going to be spaces at the edge of the box and we took advantage of that."
Hansi Flick's side were wasteful at Estadi Olimpic Lluis Companys, but ultimately got over the line to make it seven league wins out of seven matches to start the season.
Barca were without a glut of stars due to injury, with Marc-Andre ter Stegen, who is set to be out for the rest of the season, joining Dani Olmo, Gavi, Frenkie de Jong, Ronald Araujo, Fermin Lopez and Andreas Christensen on the treatment table.
The Blaugrana also rested Pedri, though his absence was not felt as Lewandowski pounced on David Soria's error to put the hosts ahead after 19 minutes.
Barca had 16 attempts in total and mustered 1.92 expected goals, yet could not find a second to put the result beyond all doubt.
Winless Getafe, though, could not make Barca pay as they slipped to a fourth defeat of the season.
Data Debrief: Lewy breaks Getafe duck
Lewandowski's winner was his first goal against Getafe in LaLiga, at the fourth attempt. He had seven shots across his previous three league appearances against them without finding the net.
Flick, meanwhile, is the third Barca coach to win his first seven LaLiga games, after Gerardo Martino in 2013 and Ernesto Valverde in 2017.
Getafe coach Jose Bordalas, on the other hand, has lost 10 of his 13 games against Barca in LaLiga (W1 D2). Only against Real Madrid (11) has he suffered more defeats in the competition.
The 19-year-old suffered the injury playing for Spain in their Euro 2024 qualifier against Georgia on Sunday, limping off the pitch in the opening 25 minutes.
Barca said in a statement that tests carried out on Monday morning have shown he has “a complete tear of the anterior cruciate ligament in his right knee and an associated injury to the lateral meniscus”.
He will undergo surgery in the coming days.
The extent of the injury is a big blow for Barcelona, who are currently third in LaLiga, with Gavi having established himself as a key player in their squad since making his debut at 17 years old in August 2021, making 111 appearances already.
He won the league title with Barca last season and has played 15 times for them this term.
Spain went on to win the match against Georgia 3-1 and Barcelona team-mate Ferran Torres celebrated his second-half goal by holding Gavi’s shirt up.
Speaking after the match, Spain boss Luis de la Fuente described the win as “bittersweet”.
He said: “It’s one of the most bittersweet victories I’ve ever had. As far as I can remember, it’s the hardest, the bitterest of moments, to see an important player like Gavi sustain an injury like that.
“It’s a very difficult moment for the player, for his club, for the RFEF (Spanish Football Federation), for the national team and for all his team-mates. In the dressing room it felt like we had lost. This is the ugly side of football.
“Football is a risky activity occasionally, something we often forget to appreciate. It was an unfortunate incident, but Gavi was perfectly fit to play the game and it was just unlucky, really, really unlucky.”
Gavi underwent surgery after suffering the injury during Spain's Euro 2024 qualifying win over Georgia last November, causing him to miss the rest of the season.
He also sat out Euro 2024 as La Roja won a record-breaking fourth continental crown, beating England 2-1 in the final at the Olympiastadion in Berlin.
On Thursday, Barcelona posted a video to social media of the 20-year-old training with his team-mates.
However, he is not expected to make his return to competitive action just yet, with Barca's next match seeing them face Catalan rivals Girona on Sunday.
Under new head coach Hansi Flick, the Blaugrana have made a perfect start to the season, with four wins from four games putting them top of LaLiga, four points ahead of defending champions Real Madrid.
Midfielder Fermin Lopez suffered a muscular problem in his right thigh while training on Tuesday, becoming the latest addition to Barca's growing list of injured absentees.
New signing Dani Olmo is sidelined for at least a month with a hamstring injury, alongside fellow midfielders Gavi, Frenkie de Jong and Marc Bernal, and defensive pair Ronald Araujo and Andreas Christensen.
Though struggling with limited selection options due to the fitness issues plaguing the visitors' squad, Flick is adamant the LaLiga leaders can adapt to find a workaround.
"When we started the season, I said there would be no excuses," Flick said. "We're going to be able to manage the game, although we'll be careful with some players carrying a lot of load.
"Tomorrow we'll manage this, although I'm sure that those who come on will be at 100%. The medical team is helping us and we are taking special care with [Pau] Cubarsi, who has been recovering."
Barcelona have made a perfect start to the LaLiga season under the German, with five straight wins putting them top of the standings, four points ahead of defending champions Real Madrid.
The only blemish on the Blaugrana's record came in Thursday's 2-1 defeat against Monaco, with Eric Garcia dismissed just 10 minutes into the Champions League opener.
"We have a great team, and we have shown it," Flick added. "Every season it's the same, there are weeks when you lose several players, but as a coach, it's something you have to accept.
"Now we have to focus on those who are available to prepare them for the next game."
Flick will at least be able to call upon returning forward Ansu Fati, who has scored four goals in six games against Villarreal in LaLiga, his most against one opponent in the competition.
Fati, along with Raphinha, Lamine Yamal and Robert Lewandowski, will hope to cover the midfield void with their attacking prowess that has propelled Barcelona to success this term.
Indeed, Barcelona are the top-scoring team in Europe's top five leagues this season with 17 goals, a tally that they will aim to add to on Sunday.
