BT Sport's Leigh Moore captured the image:
As reported by Matthew Morlidge of the Daily Mail, Moyes is said to be monitoring players from both teams. Juventus' Claudio Marchisio is being hotly tipped for a move to Old Trafford, while Davide Astori of Cagliari could offer the Premier League champions vital assurances in defence:
United have been linked with Claudio Marchisio in the past, a creative midfielder (though he was on the bench), while former youth player Paul Pogba was in action.
However, with his defence leaking goals, it could have been that the Scottish boss was keeping a keen eye on Cagliari centre-half Davide Astori.
Moyes, who was joined by first-team coach Jimmy Lumsden, picked an interesting game to attend if he is proven to be scouting either of the Italian pair.
While Marchisio started on the bench, he made a real difference when he entered proceedings after 66 minutes. The 27-year-old scored just seven minutes later to give Juve a 2-1 lead, an event that would thrust Antonio Conte's men onto a comfortable 4-1 win, per WhoScored.com.
Although Cagliari took a 21st-minute lead and kept the Serie A champions at arm's length for much of the match, Astori may regret a memorable miskick if he was trying to impress the United boss, per beIN Sport correspondent Tancredi Palmeri:
Of course, Moyes' mission may have seen him consider the talents of other players. David McDonnell of the Mirror suggests the former Everton boss was eyeing up Arturo Vidal—an individual United fans can only dream of landing at this point.
Vidal's decision to extend his contract until 2017 suggests he would be an extremely costly acquisition, per ESPN FC. Juventus have undoubtedly forced his signature in order to heighten his value, and as the Chilean midfielder continues to play a key role in the side's success, he won't leave on the cheap.
Moyes' visit to Sardinia may have offered respite during a difficult season as Red Devils boss, but it's clear the United manager is avidly working on improving a team that currently reside 10 points off the Premier League summit.
Whether he arrived in Italy with particular focus on Marchisio, Astori or anybody else, United supporters will hope any of Moyes' new signings will make a greater first impression than the hapless Marouane Fellaini, who joined for £27.5 million in the summer.