Finn Raikkonen, who replaced Hakkinen at McLaren when the double world champion retired in 2001, said at Silverstone that he is unlikely to seek a new contract once his current Ferrari tenure ends.
"Everyone does what he thinks is right," Hakkinen said in his latest interview for sponsor Hermes, "but in my opinion that was not tactically very smart.
"If the mechanics and everyone else knows that a driver intends to just hang up his helmet in a year and a half, then they will probably pay more attention to the other driver, in this case Fernando Alonso," the 45-year-old added.
Hakkinen also thinks Raikkonen's admission reveals a lot about his current state of mind.
"When you start to think about quitting," he said, "it has a negative effect on your motivation.
"You find you can no longer focus on many things that you need to focus on in Formula One."
But, unlike some others, Hakkinen does not think Raikkonen's huge crash at Silverstone was a case in point.
Some have criticised the Ferrari driver for the way he rejoined the track after running wide at the start of the British grand prix.
But Hakkinen said: "Silverstone is a good track, but why is there such a big bump?
"When a Formula One car loses contact with the ground at speed, no driver can control it anymore.
"The race has just started and the drivers are full of adrenalin, so of course he wants to come back as soon as possible. I wouldn't blame Kimi," he insisted.