World number 90 Somdev was to play in the qualifying round of the tournament but Zopp's withdrawal ensured that the Indian will get a berth in the main round. He will be spearheading India's challenge at the USD 450,000 tournament, to be held here from December 30 to January 5.
The tournament will witness top stars like world number eight Stanislas Wawrinka, world number 15 Mikhail Youzhny, world number 16 Fabio Fognini and defending singles champion Janko Tipsarevic.
Other leading players will be France's Benoit Paire, Canada's Vasek Pospisil, Spaniards Marcel Granollers & Roberto Bautista-Agut, and Frenchman Edouard Roger-Vesselin.
The 2014 edition marks only the second time in the history of the tournament when three returning singles champions form part of the playing field.
This year, 28-year-old Somdev broke into top 100 after an impressive run. In the space of 10 months, he climbed more than 550 spots to be at number 90 in ATP Ranking.
He recorded main draw wins at his first six tour-level events of 2013, highlighted by a third-round run at the Sony Open Tennis, and followed with success on the ATP Challenger Tour circuit, reaching the semifinals at four events.
Somdev also advanced to the second round of Roland Garros and the US Open and the third round of the Citi Open -- all as a qualifier -- to re-enter the top 100 by September. Somdev was also nominated for Comeback Player of the Year for the ATP.
Other leading players, who will add excitement to the event, include France's Benoit Paire, Canada's Vasek Pospisil, Spaniards Marcel Granollers and Roberto Bautista-Agut and Frenchman Edouard Roger-Vesselin.