The former Athletic Bilbao boss replaced Luis Enrique at the end of May, returning to the club that he spent two years playing for prior to moving into management.
Messi is quoted by FourFourTwo as saying: "With the new manager everything will be new. I don't know what kind of manager he is, but he is a great person.
"He was with Valencia and Bilbao, we are hearing a lot about his very good reputation, so we are pinning our hopes on this new beginning.
"Whenever I start a new season there is a very clear-cut goal, which is that Barcelona will do our best.
"Personally I am very happy and looking forward to starting a new season. We have new coaches and assistants. I would like to work with them and enjoy Barcelona for another year."
Valverde has won six trophies during his managerial career, including the Spanish Super Cup with Bilbao in 2015 after thrashing Barca 5-1 on aggregate.