The 22-year-old Slovakia international had been highly-rated at Eastlands as a youngster, where he had been tipped for a bright career.
However, the arrival of a number of high-profile signings at the club over the last few seasons has blocked his path to the first team.
Weiss joined Bolton on loan in January 2010 in a deal that ran until the end of the season.
The following campaign he was sent to Rangers where he was part of the squad that won the SPL crown during his season long-loan.
Another stint at Malaga followed last season but he is now ready for his new adventure in Italy.
"I am very happy to be at Pescara and excited about playing in Serie A," he told the club's official website.
"I hope that I can help the team to remain in Serie A and to give our fans some enjoyment. I know we have good players who did very well last season."
