The defender was part of the tour squad, but was recovering from long-term injury.
Shaw explained: "It was really helpful. It was great for team bonding I guess, he said.
"There are new players coming in and everyone needs to get to know each other better because obviously we're going to be on the pitch together at times this season.
"It was nice, but at the same time it was frustrating and a bit sad because you want to be out there on the pitch. The games we played and the players we played against, I wished I was out there playing against them.
"It wasn't to be but we've got very important games this season with Champions League, big Premier League games and cup games so there are a lot of games and I'll be ready when the manager calls on me."