Marcus Rashford needs to improve in two key areas in order to convince Barcelona to sign him from Manchester United permanently. The England forward has impressed in his first six months for Hansi Flick's side but there is still work for him to do and he is one of three players whose future at the Camp Nou is up in the air heading into the second half of the season.Rashford has scored seven goals and set up another eight for Barcelona after pressing for a loan move to the Catalans all summer. He has impressed coach Flick, who led the push to sign the attacker after he was placed in Ruben Amorim's 'bomb squad' after returning from his loan spell at Aston Villa and was barred from training with the United first team. Flick said in December: "What I can say, he's an absolute professional player. His attitude, mentality is great. In the beginning, he had to adapt a little bit, but now he's on his best level. I speak with the players when they're not playing, explaining why, and what he said to me the last day was, 'Boss, you don't have to tell me this, it's only about the team. We have to win three points, nothing else is important'. It's the right attitude. The mentality he has is fantastic and I am really happy he is here."The forward has played in all but one of Barca's matches, although his place in the starting line-up has become threatened by Raphinha's recent return from injury, with Rashford instead proving an effective impact substitute. He is also Barca's leading scorer in the Champions League. And yet despite all the progress he has made less than a year after being hounded out of Old Trafford, there is no guarantee that Barca will look to sign him permanently.A report in Mundo Deportivoclaims Rashford, star striker Robert Lewandowski and defender Andreas Christensen are all playing for their futures as their contracts all expire in June. According to the report, Rashford has 'responded well' in the first half of the season, although the coaching staff believe he still needs to improve defensively and in his pressing. The club are pleased overall with Rashford and if he continues in his current vein of form they will consider signing him permanently.Rashford's loan deal includes a €30 million (£26m/$35m) buy clause, way below the market value for a player of his track record and reputation. However, Barca are still constrained by their huge debt problems and it is believed that they will try and negotiate with United to try to sign him for a lower fee. Rashford is under contract with United until 2028 and on a massive salary reported to be £300,000 ($403k) per week, which Barca are covering the entirety of during his loan spell.Add GOAL.com as a preferred source on Google to see more of our reportingRashford has been enjoying a Christmas break for the first time in his career as La Liga paused action before Christmas while the Premier League scheduled intensified. He is loving life in Spain and is not feeling any burden.Rashford told BBC Sport last month: "I don't see anything here as like a pressure. It's just, I'm here to play football. It's been amazing. I feel welcome, I feel at home. I've just been enjoying every step of the way. It's different, but it's a great learning curve for me. And even little things, I've not done it completely yet, but learning the language and stuff like that, learning the culture, it's all enjoyable for me."It's a new language of football. I've always been, like many people in the world, an admirer of Spanish football. To play for the biggest club in Spain is a huge honour. I'm looking forward to playing more games here, just doing my best and try to help the team to win."Barca return to action on Saturday with a local derby away to Espanyol.