IndyCar said Wickens also suffered a pulmonary contusion.
He was taken by helicopter to the hospital and IndyCar said the Canadian was awake and alert when he left the track.
Fittipaldi only returned to IndyCar action in the last round at Mid-Ohio after his leg-breaking crash in the World Endurance Championship event at Spa in May. Both cars crashed into the wall, with Wickens flying over Hunter-Reay's auto and into the catchfence.
It was Rossi's second win in a row and saw him close to within 29 points of table-topping Dixon who is seeking his fifth championship.
The race was delayed almost two hours by a red-flag stoppage for track fencing repairs following a five-car incident on Lap 7.
"I was lucky to get out of that one", said Hunter-Reay, who was the first driver checked and released from the infield medical center. It was resumed after a delay of almost two hours while workers repaired a section of fencing that was damaged by Wickens' vehicle.
But even before the usual suspects edged past, Veach spoke of his desire for strong race results in these final four starts to the season, beginning with Sunday's 500-mile race.
Other drivers, James Hinchcliffe, Takuma Sato and Pietro Fittipaldi, who were also affected by the crash, were all cleared of medical examinations.
Robert Wickens went soaring into the fence at Pocono Raceway in a scary wreck that brought the IndyCar race to a halt. Hinchcliffe, runner-up on ABC's "Dancing With The Stars" in 2017, helped lure Wickens to IndyCar and Schmidt Peterson Motorsports this season after a successful career in Europe. After a almost two-hour delay, the race resumed without another spate of aggressive driving - Graham Rahal tangled with Spencer Pigot as the field was brought to green - and ended without another caution. Justin Wilson died from a head injury in 2015 when a piece of debris from a crashed vehicle bounced off the track and hit his helmet. Bourdais raised concerns about the quality of the repairs and condition of the fence before he got back in the vehicle.
Hunter-Reay, Hinchcliffe - apparently in pain - Fittipaldi and Sato all emerged from their cars unaided.
USA driver Graham Rahal - who crashed prior to the race's rolling start - tweeted his support during the lengthy delay.
It was the second crash of the race, as Rahal wrecked Spencer Pigot while the green flag flew on Lap 1. Rahal was hit with a drive-through penalty on the restart for avoidable contact.
Scott Dixon pits during the IndyCar auto race at Pocono Raceway. Wickens had reeled off five straight top-five finishes and is sixth in the standings.