The Black Cats defender was shown a straight red for a tackle on Pompey's Gareth Evans in the 67th minute, when referee Andy Woolmer felt Ozturk had denied an obvious goalscoring opportunity.
Yet, the controversial decision has since been rescinded, meaning Ozturk will be available to face Pompey in the second leg at Fratton Park on Thursday night.
An FA spokesperson said: "Alim Öztürk’s suspension has been withdrawn with immediate effect after a claim of wrongful dismissal was upheld by an Independent Regulatory Commission today.
"The Sunderland AFC defender was sent off for denying an obvious goal scoring opportunity in the first leg of the EFL League One Play-off Semi-final against Portsmouth on Saturday."
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The news may come as a shock to Pompey winger Evans, who thought the tackle 'was a blatant red card.'
Evans is also confident his side can recover from a one-goal deficit, after Chris Maguire netted the only goal of the game at the Stadium of Light.
The Pompey man also believed his side were the better side on the night, and has warned Sunderland to expect another difficult game on the south coast.
"It's still very much in the balance," said Evans after the game. "There wasn't much in it.
"There was a little bit of quality from them for their goal.
"They've got the goal, but it's only half-time and we said in the dressing room that we were 1-0 down half-time at Wembley.
"We went on to batter them in the second half - and that's fully what we intend to do on Thursday.
"There's still 90 minutes to play and it's not like the tie was over.
"At the end of the game they were celebrating like they'd won three or four nil," he added.
"It's up to them how they celebrate. We just need to be as professional as we can and do the business on Thursday.
"It's only 1-0 and there's still 90 minutes to play. We very much fancy ourselves."