Stoke City have given Leicester City permission to speak to Robert Huth about a possible loan deal.
Ivica Olic looks to be on his way back to Hamburg, with Andre Schurrle increasingly likely to join Wolfsburg.
Kettings is a free agent after seeing out his contract at Bloomfield Road earlier this summer.
The 21-year-old started his career at Manchester City before joining Blackpool in 2007.
Kettings had loan spells at Birmingham, Morecambe and York City, but it was at Hyde last season where he caught the eye.
Palace have now lined up a move for Kettings as they look to bolster their goalkeeping options and they see the 21-year-old as a player for the future.
The Scotland Under 21 international will provide cover and competition for Julian Speroni and Wayne Hennessey following Neil Alexander's departure from Selhurst Park.