The Arsenal forward was given the devastating news on Monday that he ruptured a cruciate ligament during Saturday's FA Cup victory over Tottenham.
The knee injury will rule him out of the club's title pursuit and this summer's World Cup in Brazil - four years after he was surprisingly overlooked for England's finals squad.
But Arsenal great Wilson exchanged text messages with Walcott after news of the injury broke and was encouraged by the 24-year-old's attitude.
He told Sky Sports News: "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.
"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'. He's a positive lad still in his early 20s, and you think of Aaron Ramsey with career-threatening injury he had (a broken leg in 2010) and how well he's come through.
"I know the treatment he'll get and all the positivity he has. We wish him well."
Arsenal can take some comfort from the emergence of Serge Gnabry, and Alex Oxlade-Chamberlain's impending return from his own knee injury, as they plan for months without Walcott.
But, with Nicklas Bendtner also out and Olivier Giroud recovering from injury and illness, Wilson reckons a new striker might be necessary to sustain a title challenge.
And Ray Parlour, three times a Premier League winner with Arsenal, also believes Walcott's absence leaves Arsene Wenger short in attack.
He told Sky Sports News: "It's a big, big problem for Arsenal now.
"The big question now is who's available (to sign) - I don't think managers really like doing business in the January window - they prefer to get players in during pre-season and bed them into the team.
"The likes of Dimitar Berbatov have been mentioned - he's in the last year of his contract at Fulham and Arsenal could probably get him on the cheap - that might be an option.
"People take about Diego Costa - he's having a great season at Atletico Madrid. I think he's got a 40m euro clause in his contract. But then Atletico are going really well in La Liga and in the Champions League so whether they'd want to let players go, we'll have to wait and see.
"There have been plenty of names bandied around but Arsene Wenger's got to get the right man - and he's got to get the competition right as well because Giroud should be back fairly soon - he's done really well but he could do with a bit of competition to keep him on his toes.
"It's a massive blow for Arsenal, for England - and for Theo."
Watch Arsenal continue their Premier League title challenge at Aston Villa on Monday night, live on Sky Sports 1. Kick-off is at 8pm