Charlton, who sit one place above the hosts in 19th, are unbeaten in their last four matches. Chris Powell's men have drawn three of those games, including last weekend's trip to Wigan Athletic.
Clark will be forced to make changes to the side following Wade Elliott's red card against Stoke. Peter Lovenkrands could replace him, while Nikola Zigic is expected retain his place as the lone striker.
Charlton boss Powell has no fresh injury or suspension concerns ahead of the game. Yann Kermorgant is expected to start in attack for the second game running, with Marvin Sordell on the bench.