If Kovalev doesnt return, there's 2 spots open on the top 2 lines (RW of the Koivu line, LW of the Ribs line). Right now I'd say Hossa, Dagenais, Perezhogin, Higgins, Plekanec and Kostitsyn all have a chance to get there.
The 3rd line already looks set as Bulis-Bonk-Sundstrom and Begin-Ward are a lock for the 4th line, with a spot left on their LW.
My guess?
Zednik-Koivu-Perezhogin
Plekanec-Ribeiro-Ryder
Bulis-Bonk-Sundstrom
Higgins-Begin-Ward