On 7 July 2001, Niculae completed his move to Primeira Liga side Sporting Clube de Portugal signing a three-year contract, with the option of a further two seasons for a reported fee of $3,000,000, despite it is believed that the real transfer fee is estimated around $4,500,000. He was handed the number 7 shirt, previously worn by Ivaylo Yordanov. He made his debut for Sporting in a friendly match against Académica Coimbra, coming in as a substitute in the 75th minute and netting five minutes later in a 5–2 victory. After he scored, he kissed the crest of the shirt, dedicating his goal to the team supporters.