The group of six 30-somethings had been in Boston on Friday to attend the Red Sox-Yankees game, State Police said.
The driver of the SUV, Brendan O'Hara, 33 of Cary, N.C., tried to avoid a deer that crossed in front of him on the westbound lanes of the Pike, said Lt. Bill Powers of the Massachusetts State Police.
"There was a deer in the roadway and the guy swerved and hit the guard rail," Powers said. "There were no speed issues, no other issues other than the deer."
The accident is still under investigation by State Trooper Darren Dejong and the State Police Collision Analysis and Reconstruction Section, Powers said.
Mario Zeolla, 33, of East Greenbush, N.Y., was ejected from the vehicle and was taken by New England Life Flight to UMass Memorial Medical Center in Worcester where he later died, Powers said.
Noah Sorenson, 32, of Rexford N.Y., was partially ejected and then trapped by the SUV. He was taken by ambulance to Marlborough Hospital and later died from his injuries, Powers said.
Southborough paramedics and firefighters went to the scene of the accident, said Southborough Fire Chief John Mauro.
"We ended up transporting a total of four people, two with life-threatening injuries," Mauro said. "The car rolled over and two people were ejected - one total, one partially. And the car landed on one of them."
The men killed in the wreck were seated in the third row in the back of the SUV and neither man was wearing a seat belt, Powers said.
Two men sitting in the middle row of the vehicle were hurt, but their injuries were not life threatening, Powers said. Larry Frederick, 32, of Niskanna, N.Y., and Jason Southworth, 32, from Durham, N.C., were taken by ambulance to UMass Memorial with minor injuries.
The driver, O'Hara, and the passenger in the front seat, Joseph Harrigan, 34, of Albany, N.Y., were wearing their seat belts, Powers said, and received no injuries.
State Police have been dealing with a spate of incidents involving deer this weekend.
"I guess it is that time of year," Powers said. "My contact people told me they had eight accidents statewide (Friday) night with deer."
Southborough paramedics were assisted by two off-duty paramedics - one from Boston and one from Newton - who stopped to assist.
All westbound lanes of the Pike were closed for about 15 minutes, Powers said, to allow the LifeFlight helicopter to land. Following that, the two left lanes were closed.
(Charlie Breitrose can be reached at 508-490-7461 or cbreitro@cnc.com.)