He again made his thoughts known this morning, by saying: "I am not happy".
Combined with the Spanish manager making it clear he's been frustrated by the summer transfer window, and Newcastle's activity in it so far, Benitez speaking about Perez was always going to get attention, and that's nearly certainly why he did it.
"I am not happy [with transfer dealings] but for me it is a challenge", he told Sky Sports.
The Magpies have signed five players so far this summer at a cost of just over £30million, while a number of players, including Daryl Murphy, Yoan Gouffran, Vurnon Anita and Florian Thauvin, have left.
Arsenal are set to approve a wealth of departures this month and one man on the verge of an exit could be staying closer to home, as a move to a fellow Premier League side is a possibility. "At the end of last season, Mike Ashley said he would give every penny he had to Rafa".
"We missed some targets at the beginning and we're paying for that", the Spaniard added.
"Sometimes they are unavailable, and if they are available, sometimes the wages are not the same, the commission is not the same and the wages are huge".
"We have a big squad and a lot of competition but I need to work hard and in the moments I am on the pitch, give my best", the Ghana worldwide explained.
"For me, I'm not totally happy with what we did, but I will try to do my best, working very hard with people at the club to try and improve what we have at the moment. But with his experience and know-how, he will set the team up to be very hard to beat".
"I am trying to do my best right now".