The former Real Madrid director feels the Chile star has lost confidence in his own style of play whilst playing in the shadow of the Argentine at Camp Nou
The Chilean joined Barca from Udinese in the summer of 2011, but has so far been unable to replicate his scintillating Serie A form for the Blaugrana, prompting rumours of a potential exit from the club.
Valdano believes the 24-year-old could be affected by playing in the shadow of talisman Messi, telling Radio Cooperativo: "Alexis seems to be missing confidence. He always used to have a lot of flair and took on opponents. Now he seems to prefer the safe route and pass to a team-mate.
"Maybe Messi's presence overwhelms him. You don't know how the mind of certain top players works.
"I still remember Ariel Ortega at Valencia. He used to do very well, but then Romario came onto the scene and Ortega just went missing all of a sudden."
Alexis has made 54 La Liga appearances so far for Barcelona, scoring 20 goals in the process.