“Someone of his calibre is not going to go unnoticed,” Clear told reporters ahead of this weekend’s German Grand Prix.
“But the fact is Ferrari has to move forward and we have to make the most of this situation as it is... he will be missed.”
Allison’s departure, which Ferrari said had been mutually agreed, is a big blow for the former champions and leaves the team lacking crucial technical leadership, especially ahead of next year’s sweeping rule changes.
The team did not give a reason for it, but rumours Allison would be leaving had been doing the rounds for some time.
Allison lost his wife to meningitis earlier this year and reports since have indicated he was keen to move back to the UK to spend more time with his three children.
Clear, who joined Ferrari from Mercedes in January this year, said the tragedy had hung heavy over the team.
FADING FORM
Ferrari returned to the top of the podium with three wins last year after enduring their first season without a victory in over two decades in 2014.
But the team's form has faded this season. They are second in the constructor standings, without a win, and in danger of being overhauled by rivals Red Bull, who are one point behind.
“This half of the season has been, as you see now, dominated by tragic events in March and that affected all of us - affected us emotionally, affected us practically.
“So I certainly don’t think I’ve seen Ferrari in the most enjoyable light, if you see what I mean, with that shadow hanging over us.”
Ferrari have appointed Mattia Binotto, who joined the team in 1995 and most recently headed up its power unit department, as its chief technical officer.
Given their different backgrounds, Clear said Binotto would not be stepping straight into Allison’s role.
“In that respect Mattia is going to need help from everybody,” he added.
Ferrari's German driver Sebastian Vettel on Thursday said Allison's departure would not have much impact on Ferrari at least in the short term.
Finnish team mate Kimi Raikkonen, who also worked with the Briton at Lotus, declined to comment out of respect for Allison.
(Editing by Ken Ferris)
