Timber is facing up to the prospect of missing the majority of the 2023-24 campaign as he prepares to undergo surgery on an anterior cruciate ligament injury in his right knee.
The 22-year-old was one of several players to suffer setbacks with Manchester City's Kevin de Bruyne ruled out for four months due to a hamstring problem while Aston Villa duo Emiliano Buendía and Tyrone Mings both sustained ACL injuries this month.
"There is something there," Arteta said. "In the past you can say, yes there have been games, there have been tours as well. But with games, tours, the World Cup in [December], plus this, plus that, plus internationals. It is a lot. It is too much for the players.
"It is incredibly demanding, when you see the next 36 months of the calendar for these players it is just better not to look at it because it is incredible what they are going to be doing.
"We have to look after them but, as a club, when do you look after them? To prioritise other competitions? Then we are the ones that have to look after them -- what we really need is to be sitting down, but I think it is too late, at least for the next 36 months it is too late already.
"I don't know who needs to raise a voice here but there are worries, big worries on that."
No timescale has been placed on Timber's return but sources have played down criticism his injury was exacerbated by the way he was handled in the immediate aftermath.
Timber, a £34 million ($43m) summer signing from Ajax, went down towards the end of the first half of his competitive debut against Nottingham Forest but returned for the second period only to break down minutes later.
Sources have told ESPN that Timber underwent detailed medical checks at half-time and there were no initial signs of the severity of the injury. Furthermore, the player wanted to continue and even after he left the field a second time, sources have told ESPN that Timber was walking around pain-free around two hours later.
It was only following a series of scans in the subsequent days that the full extent of the injury became clear and the decision to operate was made on Wednesday.
"To have the injury he has is a huge blow," Arteta said. "It is for the team because we recruited him with clear intentions and what he was bringing to the team was evident and he's not going to be able to do it this season for us. We have to adapt. These things happen unfortunately and we have to move on."
Arteta hinted Arsenal may go into the market to replace Timber despite already spending more than £240m this summer.
"We didn't plan with this injury," he added. "We have to assess what the options are, what are the best players that we have because, as I said, my challenge is to get the best from the players that we have.
"I cannot assess anyone who is not here. We are always open and we have to be open as well to react if something happens, not only with an injury but if something happens in the market as well. That's what we're doing.
"My focus is on getting the best out of my squad and we are open to the transfer window both ways as we still have things to do both ways, maybe."