The 19 year-old striker is now turning out on-loan with Udinese, where he will remain until the end of next season.
At NAC, the Croatian had become a fans' favourite. In his first season, he managed 35 appearances and nine goals. But he was restricted to a super sub's role and when NAC asked about extending Perica's deal into this season, Chelsea were reluctant.
However, a compromise was struck: Chelsea would forego the loan fee if NAC agreed to a penalty clause, guaranteeing Perica a set number of starts. If Perica failed to make the starting line-up at least 20 times this campaign, NAC would be up for a fee. The Eredivisie club agreed.
Graeme Rutjes, NAC's technical director, argued it was good deal: "It's nothing to be afraid of. That provision should not matter whether he plays or not. The condition of twenty matches is normally a logical structure."
However, at the winter break, Perica had managed just nine starts and Chelsea lost patience.
With little warning, Perica was pulled out of Breda and sent on-loan to Udinese.
At the time, Rutjes admitted they'd been left completely exposed.
"It is clear that we are not in the driver's seat," said Rutjes. "But I've stated this before, in our position, unfortunately, NAC do not have control. Chelsea pays for everything, his entire salary. So they decide, it comes down to that.
"Of course, an Italian club can come in and pay a loan fee of €500,000. That makes all the difference."
He conceded: "It's quite a saga, yes. It's why I'd like to know more from Chelsea."
Perica's deal with Chelsea runs to 2018. His loan in Udine expires in 2016. However, with the Pozzo family not only owning Udinese, but also Watford, it opens up the possibility of Perica turning out for the Hornets in the Premier League from season 2016/17.