Pierre-Emerick Aubameyang says his Uefa-enforced absence from the Europa League has hampered his attempts to find an early rhythm at Arsenal. The striker, who joined for a club record £56m from Borussia Dortmund on the final day of the January transfer window, is cup-tied in the Europa League – which is a huge frustration to him.

Arsène Wenger, the Arsenal manager, has criticised the Uefa rule and he believes it will be scrapped, largely because of the huge sums of money involved in mid-season transfers. Aubameyang played for Dortmund in this season’s Champions League but they finished third in their group to drop into the knockout phase of the Europa League, where Arsenal are competing.

The 28-year-old has sat out three Europa League ties so far – both legs of the last 32 against Östersunds and the first-leg of the last 16 at Milan, which Arsenal won 2-0. The return is at Emirates on Thursday. It is even more annoying for Aubameyang because the Europa League has come to represent Arsenal’s only hope of salvaging what has been a dismal season.

“I can’t play every three days,” Aubameyang said. “When I was in Dortmund, I was playing every three days but now I play once a week or have a long time between games. It is not easy. I am really frustrated because the rules are a bit … I don’t know how to say it in English but I am disappointed because I can’t help my team. That’s life. I have to deal with it.”

Aubameyang scored in Sunday’s 3-0 home win over Watford to give him three goals from six appearances for Arsenal. He has shown flashes of his quality inside the penalty area, although he has sometimes been peripheral in build-up play. Aubameyang played only once in January due to the Bundesliga winter break and problems that were linked to his transfer, and he admits he has had to play catch-up.

“It was a bit difficult at the beginning [to settle] but I am feeling better,” he said. “I didn’t play a lot in January so it was difficult to find the rhythm. Now I am feeling better. I work hard, I work a lot in the last weeks and I am happy because I feel better.”

Aubameyang has walked into the Wenger Out saga and he was asked whether the manager was taken for granted. “Of course,” he replied. “I am really happy because I am here because of him. He had the interest in me so I am happy to play for him.”