Lukas Podolski wants to return to Arsenal when his loan expires at Inter Milan, according to manager Roberto Mancini.
Neil Redfearn has taken heart from Leeds' claims that their young first-team players will not be sold in the summer.
Seaborne has won three and drawn one of the four matches he has played in since making the temporary move to The Valley.
The 25-year-old was forced to sit out the final match of his original loan spell, last Saturday's 2-2 draw against Brighton.
But Seaborne will get the chance to extend his unbeaten run in the Charlton team after a fresh deal was struck.