The 21 year-old has made just 2 appearances for the Eagles this season and joins in time for the Millers clash at Dagenham this weekend.
Cadogan came through Palace's youth development set-up and has previously spent time out on loan at Burton Albion.
We wish Kieron a successful loan spell.
Meanwhile talks are continuing with Reading about the extension of Brett Williams' loan deal which expires next Monday.
The paperwork for keeper Rhys Taylor's loan extension has also now been cleared.
Source: FOOTYMAD
