The 24-year old midfielder signed a pre-contract with the Eredivisie club in August which was to see him officially join in January.
But after linking up with the Guatemalan national team a few weeks ago, he has now opted to make an immediate move to Heerenveen and admits he is eager to get started after all the paperwork was finalised.
"Finally, everything is settled," Pappa told the club's official website. "After my matches with Guatemala would I prefer to immediately come back to Heerenveen, for me to join the team.
"Unfortunately, that is not always because of the licenses. I called every day to get everything in order.
"I'm glad it worked and I'm here. I still have to get used to the time difference, I'm going to try in the rhythm.
"I have seen Heerenveen several times at work, such as Sunday against AZ. I think we need to make some steps. Here I would like to contribute."