Gabriel Jesus has taken another significant stride toward ending his lengthy spell on the sidelines, with the striker set to feature in a friendly against Manchester United with the Arsenal Under-21s on Saturday as part of his carefully managed rehabilitation programme. It marks the latest stage of a gradual return from a devastating anterior cruciate ligament injury that has kept him out since January.Jesus' injury occurred during Arsenal’s FA Cup defeat to United at the start of the year, when he ruptured the ACL in his left knee and was forced into immediate surgery. The blow came at one of the most congested points in the season, at a time when Mikel Arteta's attacking options were already depleted, as both Bukayo Saka and Kai Havertz were in the treatment room. Speaking in May, Arteta recalled the moment with a mixture of frustration and helplessness.  He said: "It's very difficult now to understand that, if I could pause the game and say, Gabriel Jesus, we brought you back to life. You know, you are doing incredibly well. You're going to now get injured, so stop. I would stop him, bring another player in and continue to play the game. Unfortunately, we cannot do this in football."Jesus has spent the past 11 months rebuilding his fitness, working through an exhaustive conditioning programme designed to ensure he returns fully prepared rather than rushed back prematurely. After rejoining full training in recent weeks, he was named on the bench for Arsenal’s matches against Chelsea and Brentford but did not make it onto the pitch. Instead, the club opted to give him controlled exposure by organising a private friendly as he played behind-closed-doors against Watford in late November. Arteta said the session offered valuable insight into how the Brazilian’s body would respond to the intensity of real competition."It did happen. Gabi participated, and Ethan as well, because he wanted some minutes," he said. "We took the opportunity; they wanted a bit of exposure to competition, and providing that was very positive."Now, it has been revealed that Jesus is involved in a friendly against United, held at St George's Park. A statement on the Arsenal website read: "Gabriel Jesus and Max Dowman have travelled with the under-21s for a behind-closed-doors friendly against Manchester United at St George's Park as they look to build up their match fitness."For an Arsenal side that has battled through injuries to key attacking figures, Jesus's return will be timely. Havertz is still sidelined, while Leandro Trossard made a return against Aston Villa on Saturday but was forced off again. Whereas, the Gunners are also struggling in defence as their first-choice centre-back pairing of William Saliba and Gabriel are also sidelined. But games keep coming thick and fast with a busy festive schedule set to test Arsenal's squad depth. However, Arteta was not eager to pay much heed to the fixture congestion and said: "The only thing I can say is that whenever it's possible to help and give the players an extra day or hours to fulfil their maximum potential, let's do it. That's it. We are ready for tomorrow's game, that's for sure. Consistency, again, to perform at the highest level and win another game and then we'll go back to the same question, to the Champions League and then next weekend, because that's the nature of the game, and that's exactly how we have to take it every game."When asked if he was happy with the summer business and the squad that he has at his disposal, Arteta provided a measured response."We've built a squad that I believe was the best one to give us the possibility to do it," he said. "Is it what I want it to be? No, because of the injuries that we have, to have a squad means that the players have to be fit and available because that has a lot of consequences not only during matches but also in the way that we prepare for the week and the options that we have to change and keep the presence in the team. But certainly very happy with how we deal with certain situations."If his performances in training are any indication, Arsenal supporters may not have long to wait before seeing Jesus back in competitive action. Saturday’s quiet run-out against United will be another vital step, and perhaps one of the final hurdles, before the Brazilian returns to the spotlight. Arsenal play against Wolves in the Premier League next weekend, and the striker might get to feature at the Emirates after a lengthy break.