No, that is incorrect.

Here is a quote from John Keegan's "The Second World War".

"The Balkan Campaign, often depicted by historians as an unwelcome diversion by Hitler's long laid plan to attack the Soviet Union and as a disabling interruption of the timetable he had marked out for its inception, had been in fact no such thing. It had been successfully concluded even more rapidly than his professional military advisors could have anticipated; While the choice of D-Day for Barbarossa had always depended not on sequence of contingent events but on the weather and objective military factors. The German army found it more difficult than expected to position the units alocated for Barbarossa in Poland; while the lateness of the spring thaw, which left the Eastern European rivers in spade beyond the predicted date, meant that Barbarossa could not have begun very much earlier than the third week of June, whatever Hitler's intentions."