The left-sided centre-half came through the Tottenham Hotspur youth system before moving on to Port Vale and then Southend in 2010.
Newly-promoted to League One, the Shrimpers have activated a clause in Prosser's contract to keep him at Roots Hall for another season although manager Phil Brown is aware that the player is keen to play more regularly.
Speaking to local newspaper, The Echo, Brown said: "We will look at the situation again during pre-season and if Luke is unhappy then we will have another chat about things then."
The pursuit of a central defender should be one of the final pieces of Chris Wilder's transfer jigsaw after the signing of goalkeeper Adam Smith made national headlines over the weekend following his sacking by Leicester City for an incident on the Foxes' post-season tour of Thailand.