He also attended the MTV European Music Awards in London on Sunday night with his brothers Florentin and Mathias.
According to the Independent, the Portuguese is on the Red Devils' shortlist as a potential replacement for Jose Mourinho.
The Independent suggest that Andreas Pereira may be key to any move for Soler.
United will reportedly not allow a huge spend this winter and have tightened the purse strings.
The Red Devils have fallen eight points behind Premier League leaders Man City since Pogba has been out and the 24-year-old's absence seems to have affected the form of both Romelu Lukaku and Henrikh Mkhitaryan - given how well the trio were combining in the opening stages of the new season.
It is believed United would need to fork out about £40million to land the Spain Under-21 ace.
Soler has made 12 appearances this season in all competitions, scoring one goal and providing four assists, and is under contract until June 2021.
"They come loaded with games, especially during the Christmas period".