Left-back Hector, 27, has been out of action since tearing knee ligaments in September, after just three games of the current season. He missed the Billy Goats' UEFA Europa League campaign after picking up the injury little over half an hour into their 3-1 defeat at Arsenal on 14 September, but Ruthenbeck has announced that his return to training is imminent.
"I'm expecting Jonas Hector, Simon Zoller, Claudio Pizarro, Sehrou Guirassy and Nikolas Nartey to be involved," he told the Kölnische Rundschau, looking ahead to the 2 January resumption of training after the winter break.
Hector is expected to be Germany's first-choice left full-back in Russia this summer, as long as he can get back to his best after four months on the sidelines. Cologne will be hoping to have him firing on all cylinders when they resume Bundesliga action on Matchday 18, at home to Borussia Mönchengladbach.
After picking up just six points in the first half of the season, the Billy Goats have a nine-point deficit on 16th-placed Werder Bremen to make up if they are to stand any chance of staying up this season.