The Dutchman beat Kovalainen to the second seat alongside Charles Pic in 2013, with the latter surprised that his underdog heroics had been overlooked.
Kovalainen subsequently rejoined Caterham as its reserve driver, and was drafted in for Bahrain and Spain practice duties in a bid to help the team improve its car - an arrangement he is hopeful will boost his chances of a comeback.
Despite the deal, and speculation Kovalainen could return full time for the team, van der Garde says he is not concerned his own drive could be at threat.
"We have a really good contract, my sponsors are doing a good job, and the team is happy with how everything is going," he said when asked by AUTOSPORT about the safety of his current drive.
"I am making good progress in some areas. Of course we still need to work on [others] - it is not easy for a rookie, but we take it step by step.
"For me [the speculation] is a bit strange; there's nothing going on.
"Of course he [Kovalainen] speaks with the team sometimes, tries to help with what areas he thinks we can improve.
"But it's a hard situation. For him, to come to drivers like us doesn't really help the driving situation. The only thing he wants of course is to drive himself, and that's normal."
Rather than destabilise his own position, van der Garde said Kovalainen's testing duties had actually boosted his standing by establishing he is capable of leading the team's set-up direction.
"The team want to know exactly what the problem was, and he said exactly the same comments as I was saying, so that's good," van der Garde explained.
"Then the team after that is completely behind you, trusts what you say in terms of how to improve. That's very good [for me.]"
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