The 24-year-old Lewandowski was sent off in last month's shock 4-1 home defeat to Hamburg, but he will now be available for Saturday's home game with Hannover. He missed the recent games against Borussia Monchengladbach and Eintracht Frankfurt.
Poland's current Footballer of the Year was shown a straight red card for a rash challenge on Hamburg midfielder Per Skjelbred on Feb. 9. After a three-hour long hearing, Goetz Elles, chairman of the Federal Court, revealed the reasoning behind Lewandowski's ban being cut.
"It was not a kick [out]. A suspension for two games seems reasonable to me," Elles told gathered media.
Dortmund CEO Hans-Joachim Watzke was relieved about the decision to reduce his star striker's ban.
"This was a fair trial, we are very grateful. We are pleased that Robert can play on Saturday," Watzke said.
Lewandowski is currently second in the Bundesliga scoring charts with 14 goals, and he has been strongly linked with a move to Bayern Munich this summer, though Manchester United is also reportedly interested. The club has said that it will not sign Lewandowski to a new contract, meaning he will either leave for a fee this summer or next winter, or leave for free after the 2013-14 season.