MORE: A-League Preview: Melbourne City v Perth Glory
The 35-year-old ruptured a tendon in his calf and suffered ankle ligament damage early in the 0-0 draw with Wellington Phoenix on Saturday, bringing his first A-League season to a premature conclusion.
The news comes as a serious blow to City ahead of the run-in to the end of the campaign, with a showdown at home to league leaders Perth Glory coming up on Sunday.
"Especially for him, disappointment," Van 't Schip said when asked about Duff's situation.
"You know how he is, he's eager. He was every day on the pitch, giving the example, running up front, doing his work. We're going to lose someone on the pitch but also in the dressing room.
"Hopefully he will be back soon and stick around, help us out mentally with the boys because I think he can still have his presence."
The extent of the problem could yet prompt the Irishman, a two-time Premier League winner with Chelsea, to call time on his playing career altogether.
And while Van 't Schip hopes Duff will remain in Melbourne and can be convinced to extend his stay in the A-League, a decision is yet to be taken by the club or the player.
"I don't know exactly what the plan is going to be," the coach said.
"But Damien for sure is not going to ... jump in the plane and go back. He's here with his family, he wants to have a good rehab and recover. He will make his plans after that. It's just happened so I don't what his thoughts are."
City's next opponents Glory were forced to take internal disciplinary action this week when it emerged Andy Keogh and Josh Risdon were arrested following an altercation outside a nightclub after their 1-1 draw away to Adelaide United last Sunday.
Van 't Schip revealed his own players are allowed some independence in their choice of social activities away from matches, but said he would be deeply disappointed if a similar occurred with member of the City team involved.
"I expect the players to behave and have discipline, as every coach does."
"That's why they're not happy at Perth. That's not what you want.
"If we have a long turn over (between games) and we think it's good for the players to bond and have together a drink, we will say 'ok boys, go and have a drink, make sure you're at a certain time inside and know that you're out here (representing) the club."
The 35-year-old ruptured a tendon in his calf and suffered ankle ligament damage early in the 0-0 draw with Wellington Phoenix on Saturday, bringing his first A-League season to a premature conclusion.
The news comes as a serious blow to City ahead of the run-in to the end of the campaign, with a showdown at home to league leaders Perth Glory coming up on Sunday.
"Especially for him, disappointment," Van 't Schip said when asked about Duff's situation.
"You know how he is, he's eager. He was every day on the pitch, giving the example, running up front, doing his work. We're going to lose someone on the pitch but also in the dressing room.
"Hopefully he will be back soon and stick around, help us out mentally with the boys because I think he can still have his presence."
The extent of the problem could yet prompt the Irishman, a two-time Premier League winner with Chelsea, to call time on his playing career altogether.
And while Van 't Schip hopes Duff will remain in Melbourne and can be convinced to extend his stay in the A-League, a decision is yet to be taken by the club or the player.
"I don't know exactly what the plan is going to be," the coach said.
"But Damien for sure is not going to ... jump in the plane and go back. He's here with his family, he wants to have a good rehab and recover. He will make his plans after that. It's just happened so I don't what his thoughts are."
City's next opponents Glory were forced to take internal disciplinary action this week when it emerged Andy Keogh and Josh Risdon were arrested following an altercation outside a nightclub after their 1-1 draw away to Adelaide United last Sunday.
Van 't Schip revealed his own players are allowed some independence in their choice of social activities away from matches, but said he would be deeply disappointed if a similar occurred with member of the City team involved.
"I expect the players to behave and have discipline, as every coach does."
"That's why they're not happy at Perth. That's not what you want.
"If we have a long turn over (between games) and we think it's good for the players to bond and have together a drink, we will say 'ok boys, go and have a drink, make sure you're at a certain time inside and know that you're out here (representing) the club."