The 22-year-old was dismissed during the Easter Road side’s 2-1 defeat by Rangers at Ibrox at the start of the month and with the Capital club failing in a bid to overturn the decision, Porteous will miss the home game against the Terrors and the trip to Aberdeen seven days later.
Veteran defender Darren McGregor and Middlesbrough loanee Nathan Wood are the options in terms of who might partner Paul Hanlon in the backline.
"Losing Ryan is not ideal because he has been terrific for me,” Ross said ahead of Saturday’s meeting.
"Darren has played a number of times this season and has always acquitted himself well. Nathan is a young man man we brought to the club and he’s had to be patient.
"He’s played a game and a half for the England Under-20s in the international period and performed well.
"If he gets the opportunity I’m sure it’s one he will look to take because he came here to play games and he’s now going to get that chance through circumstances to try and stay in the team.”
Despite social media discussion about recruitment roles at Easter Road, Ross insists nothing has changed as far as he is concerned.
“From a football perspective, we look at the squad and the potential holes we’ll have in it come January and the potential areas we’ll want to strengthen.
"We already have Chris Mueller coming in in January, which is a big plus for us. Christian [Doidge] will be back fit, Melker [Hallberg] will be back fit, so we don’t envisage having to do a lot.
"In terms of the planning process purely from the football department, that’s remained pretty consistent irrespective of other changes around the club at senior management level."
Meanwhile, Doidge is expected to return to full training from the start of November while Jamie Murphy has shown no ill-effects after making his comeback from injury against former club Rangers and has benefited from another week’s training as he steps up his return to full fitness.