The Keeping Up With The Kardashians star, 29, and her estranged husband, 34, have been in regular contact and are said to be "talking all the time".
"It's not over yet," an insider told Us Weekly. "He thinks he could get Khloé back."
The on-screen beauty added fuel to the romance rumours by revealing earlier this month on radio that she still "wasn't over" her husband of four years.
Khloé, who recently sold the couple's marital home to newlyweds Kaley Cuoco and Ryan Sweeting, has purchased her own pad — Justin Bieber's old home in Calabasas, Los Angeles — and is said to be doing major renovations.
The latest addition includes a "subterranean basketball court," the insider added, which would fit in with former NBA player Lamar's lifestyle.
The athlete has just returned to the US after a stint in Spain where he was playing for basketball team Laboral Kutxa. Lamar had signed a two-month contract but had to end his season after a back injury.
It seems the professional basketball player is on a mission to win back his wife, as he recently revealed to In Touch that he was "going to see Khloé soon" and wanted to make it work.
While Khloé has kept mum about the status of their relationship, the breakdown of their marriage was heavily followed on her family's show Keeping Up With The Kardashians.
Khloé was seen breaking down in tears on various occasions, worrying over her future and her living situation.
Khloé cries on camera: 'What am I supposed to do?'
Earlier this month, the brunette beauty was accused of cutting off an interview with Australian morning show Sunrise when she was asked about her baby niece North West — Kim Kardashian and Kanye West's baby.
In response, actress Eva Longoria has spoken out about reality TV stars who refuse to answer personal questions.
"There's definitely things that are off-limits and shouldn't be asked (but) I think it is different for a reality star than it is for an actor," Eva told the Confidential on Nova radio programme.
"An actor goes out and acts and does work, certain things are left to be private. Reality stars are kind of living out their lives, that's why they are famous, because of the reality of their lives."