Turin-based media reported that City made an official enquiry for Juventus striker Del Piero, wanting to take the Italian superstar on loan for the season.
However, it is thought that the approach was blocked by Juve insisting that City pay 100% of Juve's wages.
Meanwhile, the Sky Sports website claims that City offered £2.7m for Danish midfielder Poulsen.
The 25-year-old is in the final year of his contract with Schalke, but a move failed to materialise as Poulsen wasn't keen on joining City and Schalke felt they didn't have time to replace him.
Schalke rejected an offer from Villarreal earlier this summer, and Poulsen was willing to join the Spanish outfit, who are in United's Champions League group.