The Italian manufacturer had originally planned to introduce a new engine for the first of two US races, but has now decided to instead phase in its upgrades over the coming races.
Ducati had trialled small chassis, electronic and engine developments in the recent test at Mugello, and will carry some of the changes into this weekend.
"At Laguna [Seca] we'll have some of the updates that we tried at the Mugello test, and those will be followed in the next races by subsequent evolutions," team boss Vittoriano Guareschi confirmed.
"We'll continue working with the settings that we've been perfecting for a few races according to our riders' respective needs, and we'll seal the fourth engines for both. Like the third one, already in use, it was made in a way that makes it possible to install new parts that are intended to improve rideability.
"The next two GPs in the United States are obviously very important for Nicky, and he would like to take advantage of the progress shown in recent weeks in order to do well for his fans. Vale came very close to making the podium at Mugello, but we must manage to give him the opportunity to be more effective in qualifying as well."
Rossi, whose Mugello testing programme was ended early by an ECU glitch, said he expected to be able to transfer some of the upgrades onto the bike this weekend. He admitted however that any changes would only be a 'small percentage' of the overall package Ducati is working on.
"Although my last test at Mugello was ended early, we were able to begin working with some details, and we'll probably be able to use some of them at Laguna," he said, "even if we're talking about a small percentage of the package that they're working on at Ducati.
"Last year we went okay at Laguna, so we'll see what happens this weekend."
Hayden, like Rossi a race-winner at Laguna Seca, urged Ducati to maintain its development rate.
"We've been getting a little closer to the front lately, but now is no time to rest. We have to keep working, because now the gains will be more difficult," he said.