The Ruhr valley club almost instantly lost their spark and attacking game when their top scorer was injured earlier this month.
They had a five-game winless run across all competitions and saw their seven-point gap at the top shrink to just three.
With champions Bayern Munich on their heels, Dortmund, more confident after last week's 3-2 victory over Bayer Leverkusen, hope Reus' return will give them their edge back.
He has not played since his injury in their Feb. 5 German Cup exit to Werder Bremen.
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The 29-year-old Germany winger, who until then enjoyed a stellar season with 13 goals and six assists, returned to team training this week but has not completed a full session.
"He is back training with the team but not the complete session yet. We have to be sensible. He has only trained twice with the team now," coach Lucien Favre said.
"He will most like be there (on Friday) but we will still have to discuss it with the team doctor," said Favre.
Dortmund lead the standings on 54 points, with Bayern, who have won the last six league titles, on 51.
"Against Augsburg we have to play a very good pressing game and play higher than we did against Leverkusen," the Swiss coach said.
After Augsburg, Dortmund host Tottenham Hotspur next week in the Champions League Round of 16 second leg with their chances slim following their 3-0 first leg loss in London.
Bayern, who travel to third-placed Borussia Moenchengladbach on Saturday, have not been spectacular in recent weeks but still extremely effective, having won 10 of their last 11 league games.
They were missing half a dozen players earlier in the week through a stomach bug and a flu virus, including Manuel Neuer, Mats Hummels and Robert Lewandowski but they are all expected to be available.
Their biggest problem is the renewed absence of in-form winger Kingsley Coman, who will be sidelined for weeks with a muscle injury he picked up in their 1-0 win over Hertha Berlin last week.
The France international, plagued by injuries in recent seasons, also missed the first half of the current campaign and had only recently hit top form again.
(Reporting by Karolos Grohmann; Editing by Amlan Chakraborty)
