The 25-year-old Chilean international moved to the Serie A giants in 2011, and has quickly established himself as a key cog in the Juventus midfield.
Vidal played, and scored, in Juventus' most recent visit to England in their 2-2 draw with Chelsea in the Champions League last week.
The Chilean first attracted the attention of Manchester United and Europe's other top clubs when he helped Bayer Leverkusen to a second-placed finish in the Bundesliga in 2011.
His impressive performances in Germany convinced Juventus to splash out to bring him to Turin, and the 25-year-old played an important role as his new club romped to the Serie A title last year, ending the season unbeaten in the league.
Reports in Germany now suggest Old Trafford scouts have been keeping a watchful eye over Vidal, and his most recent displays are thought to have provoked an inquiry into the Chilean's availability.
But any deal for Manchester United is not likely to come cheap. Vidal still has four years left to run on his Juve contract and it would likely take close to £40m to bring the Italian club to the negotiating table.