Messi only returned to the Catalan capital on Thursday after a month of recovery work and training in his native Argentina.
Martino insisted that his compatriot looks in fine shape, but is still someway short of being fully match fit.
"In my view Messi is full of desire, I think he is in very good shape physically and has the look of a killer," said Martino.
"He needs to gain more rhythm from training with his teammates and then in competitive action, but he is doing very well."
Barca are hoping that Messi will be fit to play some part in their top-of-the-table clash away to Atletico Madrid next weekend.
And Martino wants to ensure that his side maintain their position as league leaders with a win against Elche ahead of their trip to the Vicente Calderon.
"There is no reason why we should take a step back in the way we have been playing."
"The players have returned in good shape and we hope to start the league again with a high level of performance."
Despite Messi's absence, Barca have been boosted on the injury front as Victor Valdes is fit again to take his place in goal.
Neymar and Xavi Hernandez also return to the squad which won 5-2 away to Getafe last time out, but Dani Alves and Sergio Busquets miss out due to illness and suspension respectively.