Prosecutors disclosed the injury which required hospital treatment in response to claims that violence linked to loyalist flag protests has reduced.
Lawyers for a man accused of hurling a petrol bomb and being armed with a catapult during a previous riot had sought bail by citing a change in circumstances.
Kurtis Kenna, 21, of Ardenvohr Street, Belfast, faces charges of possessing and throwing a petrol bomb and having an offensive weapon in a public place.
He was arrested during one of the outbreaks of trouble in the east of the city last month.
Opposing his new bid to be released on Monday, a prosecution lawyer rejected the suggestion that the area is still blighted by unrest.
Stephanie Boyd told the court that at least 400 protestors were gathered on the Newtownards Road on Saturday afternoon.
"Police deployed two water canons, 32 tactical support group officers and in all there were over 200 people deployed," she said.
"One officer was seriously injured, he was unconscious and taken to hospital with injuries to his head believed to have been caused by a projectile thrown."
She added: "Police are aware more protests are planned for this evening."
I want to make it clear that while the present violence continues to disfigure the streets, people who have been caught up in the rioting, I will not be releasing them on bail.
Judge Justice Horner
Defence barrister Dennis Boyd said he was unaware of the latest outbreak of violence when the bail application was lodged.
"That takes the wind out of my change of circumstances," he acknowledged.
Mr Boyd referred to media reports about the demonstrations over the reduced flying of the union flag at City Hall being changed to white-line protests.
However, he pressed ahead with his application, stressing that Kenna could live at his grandfather's home well away from the riot area.
He argued that his client had no interest in flag protests, and only went to the scene out of "nosiness".
Despite his submissions, bail was refused due to the risk of re-offending.
Mr Justice Horner said he would not be releasing defendants on bail while street disorder continues but added that applications will be looked at "sympathetically... if sense prevails and people no longer engage in mindless acts of violence".