Born in San Luis, Quiroga began his career at Newell's Old Boys in the Argentine Primera División in 1997. The following year he was signed by Sporting CP, where he spent six years with a season-long loan at Italian side S.S.C. Napoli in 2000–01. He was relatively important in the Lisbon team's 2000 conquest of the Primeira Liga championship, playing alongside another Newell's youth graduate Aldo Duscher who also joined in 1998; at Napoli he played with former Sporting teammate Luis Vidigal, as they were eventually relegated from Serie A.