Known for his sublime freekicks, the South Korean, who had starred in their 4-0 rout of Mohun Bagan in the Kolkata League triumph, is recovering from a calf injury.
"At the moment there's still a question mark on Dong. He's not in right shape. We will wait and watch till the last moment and take a call after the assessment," the red and gold team coach said on the eve of the match.
The defending champions Mohun Bagan have grabbed the attention even as East Bengal, who are struggling with injuries to several players, start as underdogs.
"It's good to see there's so much of enthusiasm for the match. I don't want to say anything big here. I believe in my team and we will prove that in the result tomorrow. I'm very much satisfied with my defence and confident of a good show.
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"The derby is always about making a statement, stats don't matter. I don't want to say anything and we will see it tomorrow on the ground. You don't play derby on paper and about the statistics. Derby is different, it's about pride."
I-League winning Mohun Bagan coach Sen said they're not bogged down by the weight of expectations.
"We're always hopeful of getting three points. We don't want to talk big but to play and show on the ground. Favourites tag is not a headache. I know my limitations well, the strong and weak points."
Mohun Bagan will be facing Singapore outfit Tampines Rovers in an AFC Champions League match three days later at the same venue and Sen said they are equally focussed to do well in the prestigious continental club championship.
"I know in the past many might have said the I-League is their main target but I've told my boys that both are equally important. Yes, it's challenging for all of us and we're mentally prepared. And even if someone gets injured, we've enough bench strength. But at the moment our focus is on tomorrow's big match," he said.