The Turkey international has thrown in the towel after Die Schwarzgelben slipped 12 points behind Pep Guardiola's side after a 2-2 draw at Hoffenheim.
Jurgen Klopp's men had to come from two goals down to snatch a 2-2 draw at Hoffenheim on Saturday, a result which saw them fall 12 points behind their Bavarian rivals, who defeated Hamburg at the Allianz Arena.
Sahin admitted afterward that third-placed Dortmund has already left itself with too much to do in terms of winning the title.
"I do not think that anyone among us is so naive to still hope to compete with Bayern," the midfielder is quoted as saying by Ruhr Nachrichten.de. "They're just too far away."
Sahin added that Dortmund were deservedly punished for their profligacy against Hoffenheim.
“If you score two goals away from home, you are normally doing quite well," the Turkey international told his club's official website. "But we conceded two totally unnecessary goals in the first half, and so we first had to find a way back into the game.
"We had plenty of chances to score more goals, and we only have ourselves to blame for not taking them. We, the entire team, must find ourselves again, and then we will bounce back for sure."