Ballesteros, a five-time major winner, was on hand for a Spanish league match at Racing Santander's El Sardinero stadium, where he received a standing ovation from the fans.
Dressed in jeans and a dark blazer, Ballesteros, who lives close by, waved to fans and smiled.
The 52-year-old underwent four operations to destroy a malignant brain tumor between Oct. 5 and late December, when he was finally released from Madrid's La Paz hospital.
He is currently undergoing his fourth round of chemotherapy.
Widely regarded as one of Europe's greatest players ever, Ballesteros was known in particular for his spectacular improvisational play that helped him win three British Opens and two Masters. He also recorded 50 victories on the European Tour and is credited with having transformed European golf.
The Spaniard helped beat the United States in 1985 to begin two decades of Ryder Cup dominance for Europe, which he also captained to victory in 1997 at Valderrama.
Santander lost the match 2-0 to Almeria.