The Gunners confirmed that the 24-year-old requires surgery on a ruptured anterior cruciate ligament on Monday and will also miss the World Cup in the summer.
And former Arsenal goalkeeper Wilson says that the England international remains in positive mood, despite the serious setback.
“Having been at the Spurs game live I watched a recording on Monday, and only then did I realise how well Theo played in the central striking role,” Wilson told Sky Sports News.
“I was in the process of texting congratulations to him when I heard about the anterior cruciate injury.
“I did text him to say how well he played and that we were thinking of him and – as you’d expect because he’s such a good guy – I got a very, very positive response.
“It wasn’t a long message, but the main line coming through was ‘I will get through this’.”
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news