The 28-year-old spent a decade at the Emirates Stadium. However, he had to wait until the back end of last season for a first-team run.
A season-ending injury to Bernd Leno handed the Argentine his chance. It was one he grabbed with both hands. Martinez excelled, helping Arsenal to win a record 14th FA Cup
But, with Leno returning from his knee injury, Arteta had a decision to make.
Martinez was named in the side for the Community Shield penalty shootout win over Liverpool. However, it was Leno who got the nod in the Premier League opener.
And with Arteta wanting an established first-choice, Martinez would likely warm the bench for most of the campaign.
But, having also made it into the Argentina squad of late, Martinez decided that was not an option. As such, he opted for a £20m switch to Aston Villa.
The decision quickly came in for criticism, with Martin Keown explaining why it would come back to haunt him.
His first return to Arsenal on Sunday ended in a 3-0 win for his new side.
Speaking afterwards, he explained why he decided to push for a summer transfer.
“They called me from day one after the win against Chelsea in the FA Cup final,” he said of the interest from Villa.
“I just wanted to play first-team football and Arsenal could not guarantee me that.
“They would not say I was going to play in the first game of the season against Fulham. So when I had that doubt I had to leave and Villa were the first option and the only one for me.”
Martinez insisted Arteta was honest with him when he explained why Leno had been picked ahead of him.
“We sat down, I think he said it in a meeting.
“I was talking to him in front of a teammate as well. I told him I wanted to play week in, week out and he couldn’t guarantee who was going to start.
“Even before the Community Shield he didn’t know who was going to play in goal. After 10 years at the club I didn’t want to wait until Friday night, the day before the game, to know whether I was going to play against Fulham or not.
“So I just text him to say I was going to Aston Villa, so please help me and let me go.”