The Brazil international endured a rough return to Premier League action on Thursday (AEST) following the coronavirus pandemic, despite initially being named on the bench for the clash with Manchester City.
An injury to Pablo Mari led to David Luiz coming on during the first half, which ended with his error allowing Raheem Sterling in for the opening goal. He did not last too much longer after the interval, a foul on Riyad Mahrez leading to a red card.
The former Chelsea defender was apologetic when speaking to both his team-mates and the media after the 3-0 defeat, though his contract situation may mean he has appeared for the final time in his Arsenal career.
Asked if the 33-year-old – whose current deal is set to expire at the end of June – will feature again for the Gunners, Arteta said: "I don't know.
"He's very open, he's a man, he's a leader and I was sure he was going to speak in front of everybody. You hear what he said, he was very direct with us too.
"That's what I value from him, that's what I like from him, but a least we need to be fair on him.
"Me personally, I'm going to defend him with everything I have because I believe in him. He has shown me a lot of things in this time and his career speaks for itself."
Defeat to City leaves Arsenal in danger of missing out on Champions League football once again. They sit ninth in the Premier League table, eight points behind fourth-placed Chelsea with nine games remaining.
Arteta acknowledges that while he is keen to keep hold of David Luiz, money may dictate whether he remains at Emirates Stadium beyond the remainder of the month.
"We cannot forget the financial situation. With COVID-19 and the economy in general, it's going to have an impact," the Spaniard said.
"What the club is doing at the moment is assess the situation and try to clarify a lot of uncertainties we have in the future and we have to make big decisions.
"But time-wise it's difficult to fit them in our needs. We are trying our best, the club is trying their best and it's difficult because it puts the player or our sporting necessities in a difficult situation but again, we have to adapt.
"It's what it is and that's why I wanted to protect David yesterday, that's why I didn't start him but it's a funny game, after 20 minutes you need him and he's a player who has been with a lot of uncertainty in the last few weeks."