Campbell has won the Greek championship while on-loan with Olympiacos this season and will face the Ox's England in the World Cup.
He told RWD Football: "When he first came to Arsenal he trained with us for a week or two and then went off on loan. I saw a little bit of him and you know, he's a big talent and he showed that against Man United with that goal he scored. I do know a little bit about him.
"There's no doubt he's got talent like a lot of players for Costa Rica have and everyone else in our group."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball