Nothing strange about it. Perez wasn't good enough to start for us or get more game time.
It's hard to tell...when he did play, he showed enough to at least start over Walcott, especially with Welbeck injured and Iwobi in Bad form, as his allround game looked better. Then again, Walcott got 19 goals iirc. I think it's more down to him being rather unable to play on the wing and Wenger locked on Giroud or Alexis upfront. With Giroud and Walcott here, there never was a place for him to begin with. Definitely looks like a forced buy...by whatever circumstance.
Ironically, I think this season he Couldve excelled at the 10/ secondary striker/ winger position Özil and Alexis play.