In doing so, Nadal joked that Federer was "maybe a little contradictory" especially after hinting at playing on clay this year.
Nowhere more so than Monte Carlo where past year he became the first player to win the same ATP tournament 10 times.
Any doubts about Nadal's physical condition were cast aside, however, when he won both his matches for Spain in last weekend's Davis Cup quarter-final against Germany.
In 15 meetings on the surface, the 20-time major victor has just two wins to his name over the Spaniard - and the 31-year-old hinted that was part of his thinking when skipping the whole of the clay-court season.
Thanasi Kokkinakis suffered an unlucky fall at the end of the clay court in his first-round loss to Karen Khachanov at the Monte Carlo Masters.
'He said that a couple of days ago - and I thought he would play Roland Garros. "Then a few days later he says he will not play in one event, so there's a little bit of controversy with that".
Nadal is not the first player to question Federer's decision, with his compatriot Feliciano Lopez also describing it as a "pity". "He says he will love to play against me again in best-of-five sets on clay", came the reply.
Federer has enjoyed a renaissance by scaling back his schedule in the latter stages of his career, beating Nadal in a spectacular Australian Open final and in three other meetings on hard surfaces in 2017. Vajda has been helping Djokovic prepare for the clay-court season, and watched on during a practice session with David Goffin on Saturday.
A key factor in Federer's career resurgence past year was his controversial decision to skip the entire clay-court season. Rafael Nadal's build-up to what he hopes will be another French Open triumph begins in earnest this week when the Spaniard returns to one of his favourite old haunts, Monte Carlo.
'I always feel good when I am here, ' Nadal added.