The England man was in training, along with his fellow Three Lions striker and the £35 million Chilean.
Theo Walcott is back - and how Arsenal fans have been looking forward to his return.
Granted, he had already returned to training earlier this week. But the sight of him regularly training is at least a sign that his injury problems should be behind him (touch wood).
Questions remain over whether he will play for Arsenal this weekend. Reports suggest he will feature for the Under-21s tonight instead of against Hull City in the Premier League tomorrow, although both are a possibility at this stage.
And the 25-year-old wasn't the only one to train, of course, with the rest of the Gunners' first team in action at London Colney ahead of tomorrow's clash with Hull.
Welbeck was injured during England duty against Estonia but the £16 million striker did not sustain any serious problems, making him available for selection against Hull.
With Walcott, Sanchez and Welbeck starring, here are the best pictures from Arsenal training on Friday...