The club confirmed this week that Oliver Holmes and Peter Mata'utia would depart Wheldon Road at the end of the campaign but the futures of other players is still undecided.
Below, is every player who is believed to be out of contract with the Tigers at he end of the campaign.
1. Adam Milner
The Wakefield-born player has been with Castleford his entire professional career.
2. Jesse Sene-Lefao
The 31-year-old joined the Tigers in 2017.
3. Michael Shenton
The Castleford captain could be in his final season with the club.
4. Grant Millngton
The Australian joined Castleford in 2012 and has become one of the club's greatest overseas exports.