He also had spells at Berwick Rangers, Cowdenbeath and Clyde before making the move to Dundee last summer.
Clarke struggled to make an impression at Dens Park, making just four starts in his one term with Dundee, with 16 more appearances from the bench.
"He was a player that we tried to get last year but he was out of our reach," Pars manager Jim McIntyre told his club's website.
"Gordon Chisholm now has five strikers at Dundee so we made a call and we are very pleased that he will be returning to the club where he played as a youth.
"He caused us trouble in his days at Clyde, so we hope that he can come here and cause others problems.
"Pat will play on Saturday against a Manchester United XI and we hope that he can form a relationship with others who will be playing up front for us - Andy Kirk, Steven McDougall and David Graham."
Source: BBC Sport
Source: BBC Sport