The Croydon Advertiser says Kyriazis featured for Palace against Merstham on Tuesday evening.
"I have no idea what his surname is but his first name was Antonis, from AEK Athens, or I believe he's been there," U23 coach Richard Shaw said.
"I don't know the full story of it yet, it's something Mark Bright is dealing with at the moment.
"I thought he came on and showed some good touches and produced a good understanding of being a No.9.
"Like I said, I'm not sure what the whole protocol is with the trialists are, but we gave him 20 minutes (at Merstham) for a workout and he was quite impressive at times."