2016 US Olympic Track and Field Trials: What to Watch for on Day 8

The seventh day of the U.S. Olympic Track and Field Trials goes down Friday from Eugene, Oregon. NBC Sports Network and NBC Sports Online will broadcast the day's events beginning at 6 p.m. ET.

Everyone's always interested in who will win or place high enough in each event, and in so doing stamp their tickets for the Olympic Games. On Friday, several events will name their entrants to Rio. Not only that, but they happen to come in some of Team USA's signature events.

Let us now take a look at what lies ahead in Eugene.

Allyson Felix Continues Bid for Rio Double Gold

If she accomplishes her goal, Allyson Felix will be in rarefied air.

The quest resumes Friday, when she will attempt to make the Summer Games in the 200-meter race. She already qualified in the 400. If she can add this, then take gold in each race in Rio, she'll be only the third woman to do so.

The trip to Rio also will be the fourth Olympic appearance for Felix, who already has a gold medal in the 200 and three for her roles in relay events.

Adding drama to the mix is the fact she's coming off an ankle injury that kept her out of action for one critical month this spring.

"It’s been a really difficult year,” she told Rick Maese of the Washington Post. “Things have definitely had to be altered a bit. ... Definitely had to just kind of take a pause and kind of have a new plan to put things together. It’s been a very rocky road.”

But she's here now, and the all-time great sprinter is set to add a little more gold to the trophy case. The 200 prelims take place Friday.

Aries Merritt Strives for Olympics After Kidney Transplant

The men's 110-meter hurdles begin Friday, and all eyes will be on Aries Merritt. 

The 30-year-old Chicago native is trying to defend the gold medal he brought home from London, but he'll do so after undergoing a kidney transplant.

David J. Phillip/Associated Press

A rare disease resulted in Merritt undergoing the surgery, which involved a kidney received from his sister. 

It's a terrific story, but with the specter of the Zika virus looming and his immune system still potentially compromised, Merritt's doctors are "very, very concerned" about his potentially competing in Brazil, according to the Associated Press.

Here's hoping for the best outcome, whatever it may be.

Dawn Harper-Nelson Goes for Third Olympics

The great hurdler nabbed a gold in the 2008 Beijing Games, and a furious comeback in 2012 delivered a silver. 

Now, at the age of 32, she has qualified for Friday's semifinals (the finals also happen Friday) and is looking for a seat on the plane to Rio.

But it won't be easy. Kendra Harrison, Nia Ali and Brianna Rollins—the latter of which ran the fastest time Thursday—are all worthy competitors in their own rights.

"

Women’s 100H first round up now. This…will be interesting.

Watch #TrackTown16 on @NBCSN & @LiveExtra! https://t.co/HDQA7KRqy4

— USATF (@usatf) July 8, 2016"

Evan Jager And Then Who?

The 3000-meter steeplechase doesn't have the same cache as something like the hurdles, but it's still darn fun to watch. Think of it like a stylized Tough Mudder. 

In this event, which will have its finals Friday, the current kingpin is North American record holder Evan Jager, who's looking to make his first Olympics. According to Dennis Young of FloTrack, he's "the definition of a lock."

"That leaves Dan Huling, Cory Leslie, Andy Bayer, Donn Cabral, Stanley Kebenei and Donnie Cowart as credible contenders for two Olympic slots," Young wrote. "Jager, Huling and Bayer could give coach Jerry Schumacher another sweep."

Jager gives Team USA its best hope for a medal in Brazil. His running mates are more of an open question.