Those of us who have long since lost interest in this term’s moribund title race were given plenty to get our teeth into prior to Sunday’s US grand prix as several teams opted to ring some major changes.

Sergio Perez’s announcement on Twitter of his impending exit from McLaren was the most surprising, given that the talented Mexican has been at the team for less than a year.

Just hours after Perez broke the news of his departure at the season’s end, the Woking marque named his replacement as 21-year-old rookie Kevin Magnussen, who will be promoted from development driver for the start of the 2014 campaign.

The first rookie to be bumped up to race driver at McLaren since Lewis Hamilton, Magnussen has already expressed unbridled joy at getting his dream drive — though many have seemed much less pleased by the turn of events.

One of those left somewhat bewildered by the turn of events is McLaren’s main man Jenson Button, who didn’t sound particularly thrilled at the prospect of working with the young Dane.

“It’s important to have a team-mate who has experience and Kevin doesn’t have that,” Button said.

“There are two ways of looking at it — that experience doesn’t count for so much these days because of the new regulations and it’s a very different way of driving a racing car, which it will be next year.

“So there’s that way and you can say he is in a good position, but an experienced driver knows what he can do to adjust the car, develop it and move it forward.”

Elsewhere veteran Heikki Kovalainen made a surprise return to Formula One as he jumped into the Lotus seat left vacant by fellow Finn Kimi Raikkonen.

After the latter revealed last weekend that he would miss the final two grands prix of this season in the United States and Brazil — and after Lotus tried and failed with bids to lure Michael Schumacher out of retirement for a second time and then to sign Nico Hulkenberg from Sauber — Kovalainen jumped ship from Caterham, where he was employed as a reserve.

And while the smart money is on either Hulkenberg or Pastor Maldonado taking the seat on a permanent basis next season, Kovalainen has two races in which to impress.

Speaking of Maldonado, the Venezuelan put the boot into one of the sport’s ailing greats when he announced his pleasure to be leaving Williams.

At the season’s end Maldonado will conclude a three-year relationship with the Grove-based marque, which has just suffered the worst year in its history in terms of on-track results.

With just one championship point on the board, won, earned by the south American when he finished 10th in Hungary, Williams will hope his replacement Felipe Massa can do better next season.

But for now the once-dominant marque was forced to suffer the indignity of having Maldonado publicly admit he was happy to be going.

“I wanted to leave the team, and I’m happy about that,” he said. “Overall, I feel I delivered more to the team than they did for me.”