David Moyes revealed he was surprised after Manchester United allowed Danny Welbeck join Arsenal.
The England international was informed his services are no longer required by manager Louis van Gaal as the Red Devils are willing to let him join another club on a season-long loan. However, the 23-year-old was looking to leave only on a permanent transfer and he completed a switch to the Emirates on the final day of the summer transfer window.
The former Everton boss managed Welbeck at United during his short spell at Old Trafford. The striker came up through the ranks of the club's youth setup and Moyes has raised concerns over Van Gaal's decision to let the player join Arsenal.
"Danny Welbeck was great for us at Manchester United. We played him in nearly all the big games and, more importantly, [he was] one of your own boys you bring through," Moyes told BBC.
"There are not many young British players out there, so it was a bit of a surprise for me [that he was sold to Arsenal]. But whoever is in charge has to decide what route they choose."
Meanwhile, Welbeck has been a key player in the Gunners' starting lineup and has been Arsene Wenger's first choice striker for the league and European fixtures as Olivier Giroud is still recovering from his injury.
The former United striker has already scored five goals in all competitions, which include a late strike that helped his side avoid a defeat in a 2-2 draw against Hull City. Welbeck has expressed his frustration after Arsenal failed to pick three points against the Tigers.
"It was bittersweet because we started the game well. They got the early goal [in the second half] and made it difficult for us because they just sat back. I was pleased to get a goal but disappointed not to get the three points," Welbeck told Arsenal's official website.
"There's different ways you can look it at because they've been working hard all game, they maybe got a bit tired towards the end."
"You don't see those sort of things on the pitch but being on the pitch makes things more difficult. We need to see how we can evaluate it from there," he added.