Rodriguez crashes out of Amstel Gold
A view of the pack during the 49th edition of the Amstel Gold Race in the province of Limburg, the Netherlands, on April 20, 2014 - by Bas Czerwinski
The 34-year-old Spaniard could well miss the Fleche Wallonne, a race he won in 2012, on Wednesday after complaining of dizziness.
"Purito definitely out. @PuritoRodriguez hit by other rider," said his Katusha team's press officer Philippe Maertens on Twitter.
"Too dizzy in head to continue. Too early to say something on coming races."
Katusha later tweeted that Rodriguez had been taken to hospital for chest X-rays.
Although the Amstel course isn't the most ideal for Rodriguez's explosive characteristics, it is in the three Ardennes Classics that he has had some of his best results.
He finished second in 2011 at Amstel while he has had two second place finishes on both the Fleche Wallonne (2010 and 2011) and Liege-Bastogne-Liege (2009 and 2013).
He wasn't the only big name to crash out as former Tour de France winner Andy Schleck's miserable season continued when he was forced to abandon.
He was brought down in the same incident as Rodriguez around 80km into the 251.8km race.
Schleck got back on his bike and rejoined the peloton, only to abandon around 40km further down the road.
The Luxemburger, who won Liege-Bastogne-Liege in 2009 and was awarded the 2010 Tour de France victory after Alberto Contador was stripped of his win for doping, has not recovered his form since fracturing his pelvis in a crash at the 2012 Criterium du Dauphine.
His best result since then was an underwhelming 20th at last year's Tour de France.
Irishman Dan Martin, the current Liege champion, was another rider to abandon, along with Team Sky's Welshman Geraint Thomas, who enjoyed top eight finishes at both the Tour of Flanders and Paris-Roubaix over the previous two weeks.
The Amstel Gold Race is known as one of the most dangerous on the World Tour calendar due to its tight winding roads and numerous central reservations.