Welbeck joined the Gunners on transfer deadline day from Manchester United, where he had become frustrated at a lack of opportunities in his preferred central striker role.
Since the return to fitness and form of Olivier Giroud, who spent four months out with a broken leg, the 24-year-old has found himself deployed on the flank of a front three along with Alexis Sanchez, rather than down the middle.
Welbeck was a late substitute for both of the previous two Barclays Premier League matches, but could face his former club in Monday night's FA Cup quarter-final at Old Trafford.
Wenger is convinced Welbeck, who has seven Arsenal goals, can play a big part in the future of the team, but like everyone else has to earn their place in the starting XI.
"Danny Welbeck puts big team effort in, he plays very well for me and is an exceptional player who will have a great future here," said Wenger, who confirmed centre-back Gabriel Paulista was set for "two to three weeks" out with a hamstring injury suffered in the midweek Barclays Premier League win over QPR at Loftus Road.
"The subject is raised because he is a former Man United player, (but) I am very, very happy that I bought him."
Wenger continued: "Welbeck is very important and has played many, many games since the start of the season.
"His position is one of the three up front, central, left or right
He can play anywhere."
England forward Theo Walcott is another who has watched on from the bench in recent weeks, as Wenger finally enjoys the luxury of strength in depth.
The Arsenal boss added: "We have a lot of competition going on in the team, especially up front - we have plenty of offensive potential
It makes every decision more difficult
"People always raise these kind of questions when (either) you do not have enough players, or when you do have enough players.
"(However), we have chosen a job where competition is part of our job
That means we can't complain about that, because we have made that choice.
"Our job is to serve the club and to compete with other people to do as well as we can to serve the club.
"The only important thing is what the club achieves - all of us are only here for that."
Arsenal have a poor record at Old Trafford, not winning since September 2006 and suffering an 8-2 thumping there in August 2011.
Wenger, though, sees no reason why the Gunners, who are ahead of United in the Premier League table, should not be able to produce the required performance this time around.
"I don't believe too much in history, I just believe in the performance on the day," he said.
"At the moment we are doing very well away from home
The size of the pitch is exactly the same everywhere, it is just down to how much we turn up and how much effort we put in to win the game.
"Both teams will think if we get over this hurdle, we have a good opportunity to win the competition.
"We are confident from our Premier League run, so w e go to Manchester United to qualify and to give absolutely everything."
Wenger, meanwhile, rejected criticism of Mesut Ozil by former Manchester United midfielder Paul Scholes, who claimed the German playmaker was only "going through the motions" at Arsenal.
"I think a player like Paul Scholes would have loved to play with Mesut Ozil," Wenger said.
"We are all in a job where in every single game we have to prove a point.
"I believe Ozil has the quality, he puts a lot of effort in to help the team and he works much harder than his style shows.
"You can be cheated a little bit by his style of play, because he is fluent, easy, subtle and he does not look like he puts the effort in, but he does."
Source : PA
Source: PA