Returning drivers need year to be back on pace – de la Rosa
The highest profile returnee in 2010 is Michael Schumacher, but Spaniard de la Rosa – two years younger than the great German – is also back in F1 full-time after seven years as McLaren's test driver.
"At the highest level it is not easy," the Sauber driver said at Silverstone.
"As the season goes on it is getting better. After a few races you are simply not yet right back on top," added de la Rosa.
"To really be there again, you need a full year."
De la Rosa insists he was never completely away from the cockpit; he was regularly at the wheel of McLaren's state-of-the-art simulator, and occasionally tested on track.
But "in order to really compete with these guys, you probably need a whole year," he added.