The struggling club have lost both of their La Liga games so far this season and hope to break their duck when they host Getafe.
But their faltering start to the campaign has failed to persuade Martinez that reinforcements are required.
"I am very happy with the squad and am totally convinced that we have many qualities," he said.
"It has already been said that there won't be any more players coming, except at zero cost. I'm satisfied with what we have."
Martinez has implored his players to attack with greater urgency when they face Getafe, who have secured only one point so far this season.
"We want to own the game and we do that by having the ball. Indeed, we must be quicker in moving the ball forward to hurt opposition who have good attackers," he said.
"We know what we want and what our purpose is, it is still too early in the season to be worried."
Getafe coach Luis Garcia is unconcerned by his side's start to the campaign.
"I'm optimistic for this game, but Valladolid will also want to win front of their own fans," he said.
"We know we haven't won yet, but let's stay calm. This is just the start of a season that is very long and will contain some good results, some bad."