The striker has struck twice in preseason action since his return was confirmed by manager Sir Alex Ferguson.
Valencia told manutd.com: "All the players are feeling good about the new season. There is a great team spirit amongst everyone. I love being part of this team – I have some good friends here and I laugh a lot with guys like Evra, Nani, Anderson, Bebe and Chicharito, but everybody in the group has a laugh together. When we have to work, we take things seriously. When the time is right to enjoy ourselves, we do that too."