Messi has scored eight league goals so far during an injury-hit season, after managing 96 across the previous two campaigns.
However, head coach Martino is pleased with the way other forwards - such as Neymar, Alexis Sanchez and Pedro - have responded in light of Messi's recent absence.
The Argentine has now returned to full fitness, but Martino is happy to see goals being spread around his squad to lessen the pressure on Messi.
"The important thing is there's not so much responsibility on Messi to score these goals," said Martino during a press conference on Friday.
"This happens in all teams, and there have been occasions where one player has more responsibility in front of goal. That hasn't been the case and that's been a benefit to the team - they grow in terms of their morale."
Neymar is not available to face Valencia on Saturday, despite returning to training after suffering an ankle injury.
Martino is refusing to rush the Brazilian back despite a UEFA Champions League last-16 clash with Manchester City looming on the horizon.
"I have to be respectful about what I'm told by the medical staff and physio," he added. "I am not thinking in terms of City. I hope he will be fit for that game.
"If he's fit he'll play before, if he's not fit he won't play. The importance of the game doesn't make sense to play him and put him at risk.
"He'll come back when he's fit and ready."
