The winner of Thursday's race, held at 5 p.m., will represent the United States in the Summer Games, pending Olympic Committee approval.
On Wednesday, as the teams glided toward the boathouse after the second race, Guregian watched. He pressed a cellphone to his ear.
"We did what we could, man," he said. "I know. It [stinks]."
Guregian, 23, of Los Angeles, was talking with his teammate, Temple women's rowing coach Jason Read. Four hours earlier, both men felt confident, Guregian said. They were supposed to breeze through the semis, putting them one step away from a trip to London.
On Tuesday, Guregian and Read smoked their competition, beating their heat's second-place team by about eight seconds. But when the two warmed up before Wednesday's race, Read said he needed to stop. His back locked.
Read, who 11 years ago searched for survivors among the rubble at ground zero on 9/11, couldn't even stand Wednesday. His mother drove him to the hospital, and event officials pushed the race to noon. They hoped he could recover in time to compete. He couldn't.
X-rays didn't show any structural damage, but doctors would not clear Read for competition.
"It's a terrible feeling to go from being an elite Olympic athlete training for your third Games to not even walking," Read said. ". . . To have four years of focus extinguished, it's devastating."
Guregian watched the second race from the boathouse and thought about the sacrifices that drove him to the edge of Mercer Lake, and the Olympics. In January, he was one of 20 rowers invited to a camp to try out for the U.S. men's eight. But when the camp wrapped April 30, he didn't make the cut.
A couple of days later, Guregian called Read, whom he rowed with in 2010. Read, 34, won an Olympic gold medal with the men's eight in 2004, and he also competed at the 2008 Games. Some thought he was over the hill, Guregian said, but that wasn't true. The two blew past people.
Soon, Guregian will fly back to California, any hope of the Olympics at least four years away. This summer, all he will do is watch.
Contact Tyler Jett at tjett@phillynews.com.