The new boss, credited with revitalising a stagnating group after his summer arrival, has preferred Gerard Pique and Samuel Umtiti as his premier centre-backs so far in 2016/17. But Messi is apparently now on the case to get Mascherano onto the pitch again.
The claim comes from Don Balon, which states that Messi has 'spoke with' Valverde about Mascherano's situation - the veteran has been an unused substitute for every game since starting the opening game of the new La Liga season almost a month ago.
It is said that Valverde hasn't been overly impressed by Mascherano on the training pitch, yet he still apparently reassured Messi that the 33-year-old will get some playing time sooner or later.
That could come as early as Tuesday or Saturday, with Barça facing games in quick succession against Eibar and Girona in the coming days ahead of a Champions League clash with Sporting CP in Portugal next week.
Messi is no stranger to influencing managers at Camp Nou. Zlatan Ibrahimovic blamed the Argentinean for his ultimately short stint in Catalunya after being made to play out of his favoured position by then coach Pep Guardiola because Messi wanted to play more centrally.
After winning a fourth career European Golden Shoe last season, Messi has started the new campaign in equally fine form with five goals in his first four league games. It would therefore be a brave coach to ignore or go against his requests at Camp Nou.