2009 World Rally Championship runner-up Mikko Hirvonen has admitted his fears that compatriot Kimi Raikkonen might struggle to succeed in his first season of top-level rallying should he indeed make the leap from F1 to the WRC in 2010.

Sources claim that now only a few minor details are standing in the way of an agreement between the 2007 F1 World Champion - evicted from Ferrari a year before his contract was due to run out in favour of fellow title-winner Fernando Alonso - and multiple WRC champions Citro?n, with the deal to be facilitated by Red Bull, which sponsors both driver and team [see separate story - click here].

The Finn's manager Steve Robertson has hinted that a 2011 F1 return with Red Bull Racing might be on the cards following a sabbatical in the WRC, but others are not so sure Raikkonen will find it quite that easy to reclaim his place on the grand prix grid following a year away.

Four-time world champion Alain Prost has warned the 'lazy', party-loving 18-time grand prix-winner that if he fails to apply himself in the WRC, there may be no way back [see separate story - click here], and Ford star Hirvonen - who will renew his battle with record-breaking Citro?n rival S?bastien Loeb in 2010 - suggests that Raikkonen will have his work cut out right from the start.

"Kimi is fast and with driving he doesn't have problems," the 29-year-old told Finnish website Sportti.com, "but preparing to drive with pace notes is a difficult case for him.

"We WRC drivers have so much more experience, and almost all the rallies will be unknown to Kimi in advance. It's difficult to imagine that Kimi could succeed, at least in his first season."