The Manchester United forward was thought to be a doubt for their first Group D fixture in Manaus after limping out of training on Tuesday.
But, addressing the media in Rio de Janeiro, striker Wayne Rooney confirmed: "Danny will be fine.
"He's just not risked anything today but he'll train on Friday and he'll be available for Saturday for sure."
Welbeck, 23, took part in the early part of yesterday’s session in Rio with strapping over his thigh and was later withdrawn.
He missed Wedneday's open session along with Alex Oxlade-Chamberlain, who continues his recovery from the knee ligament injury he sustained against Ecuador last week.
Despite Welbeck's apparent availability, manager Roy Hodgson has spoken of the wealth of attacking options at his disposal.
Sky Sports News reporter Nick Collins, who watched the open part of the session, said: "There was a feeling we might have seen him today but England are being very cautious with Welbeck.
"That may be a good sign but unless he is fully able to play a part in training by Friday this would rule him out of playing against Italy on Saturday.
"It's a concern at the moment, but there is still time for Welbeck to recover, although there has been no official update from the FA.
"It's a case of wait and see but Roy Hodgson has other alternatives if Welbeck fails to make it. He could go bold and bring in Raheem Sterling, who has been dazzling everyone in training with his performances.
"They rate him very highly and he could slot in on the left or right with Wayne Rooney in the centre.
"But he could change things even more if he was to go for Ross Barkley and move Rooney to the left to play the Danny Welbeck position.
"Barkley was very impressive when he got the chance to play in that position against Ecuador in his first England start."
Whether Welbeck is fit or not he may not be too badly missed according to the results of Sky Sports' England Team Selector.
The striker has only been included in seven per cent of sides with Sky Sports users preferring the likes of Adam Lallana and Raheem Sterling in the starting XI.
Keep up to date with the news from England's training camp in Rio From Nick Collins throughout the day on Sky Sports News.