Clevid Dikamona has signed a one-year contract extension with Hearts until 2020.
The Congo international centre-back has impressed since arriving on a free last September, making 21 appearances including 12 starts.
Hearts boss Craig Levein also confirmed his interest in Livingston defender Craig Halkett but would not discuss how close the deal is to completion.
"I'm quite happy with the way things are going," Levein said.
"I know it's a bit away but I'm quite happy with how we are looking going into next season.
"I think we will only need to make two or three signings in the summer, all being well."