The British No 2 was trailing 3-2 in the first set when he decided he could no longer continue because of a hip injury.
Edmund may have been counting the cost of his run to the semi-finals at the European Open last week, which sent him up to a career high world ranking of 40.
The 21-year-old beat Ferrer on his way to the last four in Belgium, where his challenge ended against Frenchman Richard Gasquet. But hopes of a repeat were swiftly dashed when Ferrer broke in Edmund’s opening service game. After only 18 minutes, the young Yorkshireman shook hands with his Spanish opponent at the net citing injury.
Meanwhile, Andy Murray has his sights set on prising the world No 1 ranking from Novak Djokovic after a stellar 2016.
Djokovic has topped the rankings since July 2014 but a dip in form, coupled with Murray’s superb results, has put the Serbian’s reign in jeopardy.
Murray’s win at the Shanghai Masters earlier this month means the Scot could reach the summit as early as November 7 if he wins the title in Vienna and the upcoming Paris Masters, provided Djokovic does not reach the final in France. The Scot begins his campaign in Vienna today against Slovakia’s Martin Klizan.