Christophe made 65 appearances in two seasons at Southend
Lincoln City manager Steve Tilson says injury issues have delayed his efforts to sign Jean-Francois Christophe.
The midfielder, 24, played under Tilson at Southend and has trained with the Imps but currently has a thigh injury.
Tilson told BBC Lincolnshire: "I've told him that as long as he's OK in the next two weeks then the deal is done.
"Everything's agreed but I have to make sure he's definitely fit. It's a small squad and I don't want the chairman to think I'm signing an injured player."
Frenchman Christophe joined Portsmouth from RC Lens in 2006 and spent time on loan at Bournemouth and Yeovil before Tilson took him to Southend in September 2008.
He made 65 appearances for the Shrimpers before departing at the end of the 2009-10 season, and after an unsuccessful spell with Oldham returned to France.