The former NBA player, 34, has been in Spain for the past couple of months where he was playing for the Baskonia basketball team. Lamar had signed a two-month contract but had to end his season after his injury.
"I'm focusing on getting better," he added. Lamar and Khloé's marriage is said to have fallen apart because of the sportsman's reported drug addiction and rumours of his infidelity.
A family insider added that Khloé, 29, was giving her troubled relationship with Lamar another chance, despite warnings from friends and family.
"He confessed his feelings and cried his heart out to her on the phone," the source said of the mid-March phone conversation. "She'd been avoiding his texts and calls for weeks, but when she heard him pleading with her to take him back, she melted."