Press Association Sport understands the Holland midfielder was heading from Ukraine to the north-east on Tuesday night after the two clubs agreed a fee in the region of £8million.
However, as the Black Cats prepared to push home their interest in the Dynamo man, sources close to the club have indicated that their interest in Zenit St Petersburg defender Nicolas Lombaerts has been shelved because of an issue picked up by medics.
Rumours that the 30-year-old Belgium international had failed a medical began to circulate on Tuesday evening, and it is understood that a proposed £5million transfer has now been put on hold.
But if that came as a blow to Advocaat, whose side lost 1-0 to Sacramento Republic in the United States during the early hours of Wednesday morning, the news on Lens is far more encouraging.
The 27-year-old, who worked under his compatriot at both AZ Alkmaar and PSV Eindhoven, watched his current club's 2-0 Ukrainian Super Cup defeat by Shakhtar Donetsk in Odessa from the stands on Tuesday evening before setting off for England.
Sunderland are hopeful of concluding a deal within days to allow the player to meet up with the rest of the squad in America.
Source : PA
Source: PA