The first-choice goalie has been missing for the struggling Russians for over a month since suffering a broken foot.
But he returned to full training yesterday and could face Celtic tomorrow. Spartak have been jinxed this season as three of their keepers have suffered long-term injuries.
Andriy Dykan and Artem Rebrov have both been sidelined with shoulder injuries.
But Pesyakov, who played against Celtic in Moscow in the Champions League in October, has convinced caretaker boss Valery Karpin he's fit enough to travel to Scotland.
And he will give Karpin a selection dilemma about whether to recall the highly-rated 23-year-old or stick with 35-year-old Dykan.
Meantime, the crunch tie will be refereed by German official Felix Brych. The 37-year-old is a doctor of law and one of the most respected whistlers in Europe, after being handed last season's semi-final between Chelsea and Barcelona in London.
Brych has never been in charge of a Celtic match, although he has twice refereed Rangers games. He was the man in the middle of a 2010 Group Stage tie when Valencia beat the Ibrox side 3-0 and was also in charge when Rangers gained a 1-1 draw in Panathinaikos on their way to reaching the 2008 Uefa Cup Final.
But Dr Bryce was at the centre of controversy last year when his house was raided by German authorities when he was probed for tax evasion.
He was eventually cleared and went on to officiate at the Olympics this year in London too.