Ferrari president Luca di Montezemolo was told by Italy's influential La Gazzetta dello Sport that Alonso, the 2012 runner-up, appeared almost "in hiding" throughout the pre-season period.
"I don't see it that way," Montezemolo insisted.
"But I understood his fears in the first test, when he didn't want to talk because he had to understand the possibilities of the F138.
"I hear from him almost every day. He is calm and confident," he added.
Alonso's manager, the former Renault boss Flavio Briatore, also acknowledged the double world champion's low-profile winter.
"He first wants to race, to really see where the (2013) Ferrari is. That's why from the outside he may appear tense, apprehensive," the Italian said.
"He is pleased with the outcome of the tests but as always you don't know where the others are exactly.
"Fernando is hoping that the gap to Red Bull has reduced. If he can start on par with the others, he will surely win the world championship."
Win or not, Montezemolo is sure Alonso "will respect" his contract, which is set to run to the end of 2015.