When it comes to just name value alone, we do. Reyes (12-2) fought Jon Jones for the UFC's light heavyweight championship 14 months ago -- and many observers thought he should have won the judges' decision in that fight. Prochazka (27-3-1) has been a champion in another promotion, and he made a splash in his UFC debut last year.
As these two prepare to meet Saturday in Las Vegas, we certainly know of them. But in terms of who each of these men is within this division, we still don't.
Is Reyes, 31, the man who nearly toppled Jones back in February 2020? Or is he the guy who looked lost in a title fight against Jan Blachowicz last September? Reyes lost that bout via TKO, and he never really looked comfortable at all. He has since said that he wasn't himself that night, that he lost a little bit of his identity after the Jones loss and because of health issues in his family.
And as for Prochazka, is he a legitimate title challenger or merely a fun wild card in the division? The 28-year-old is extremely unorthodox, which makes him exceptionally dangerous. He is on a run that has seen him finish nine consecutive opponents -- seven inside the first round -- and it hasn't been easy for the UFC to find him an opponent. But in terms of proving his fighting style will consistently work against the elite of the division, this fight should tell us a lot.
Look, even though Blachowicz has clearly established himself as the king of the 205-pound division after Jones' exit in 2020, this weight class is still wide open. If Reyes really is the guy who pushed Jones to the brink of defeat two fights ago, he is capable of winning a UFC title this year. And if Prochazka really is a fighter of substance, the same can be said of him.
Right now, we can't say with certainty who these guys are within this division. That should change come Saturday night.
By the numbers
0: Losses by Reyes in nontitle fights. He is coming off his only two defeats, and both came in bouts with the light heavyweight belt on the line.
11: Consecutive victories for Prochazka, all but one of them coming by knockout.
1: Victories among the 27 in Prochazka's career that did not come via stoppage.
4.53: Strikes landed per minute by Reyes in the UFC, the fourth most among active light heavyweights. Prochazka landed 5.7 per minute in his July debut against Volkan Oezdemir but does not qualify among the stats leaders because he has only that one UFC bout.
2: Male fighters who have won their UFC debut against an opponent ranked in the promotion's top 10 (since UFC rankings began in 2013). Prochazka is one, knocking out Oezdemir in his Octagon debut in July. The other is Justin Gaethje, who debuted with a win over Michael Johnson in 2017.
Sources: ESPN Stats & Information and UFC Stats
Five vs. five
Dominick Reyes' most recent results
Loss: Jan Blachowicz (TKO2, Sept. 27, 2020; watch on ESPN+)
Loss: Jon Jones (UD, Feb. 8, 2020; watch on ESPN+)
Win: Chris Weidman (KO1, Oct. 18, 2019; watch on ESPN+)
Win: Volkan Oezdemir (SD, March 16, 2019; watch on ESPN+)
Win: Ovince Saint Preux (UD, Oct. 6, 2018)
Jiri Prochazka's most recent results
Win: Volkan Oezdemir (KO2, July 12, 2020; watch on ESPN+)
Win: CB Dollaway (KO1, Dec. 31, 2019)
Win: Fabio Maldonado (KO1, Oct. 12, 2019)
Win: Muhammed Lawal (TKO3, April 21, 2019)
Win: Brandon Halsey (TKO1, Dec. 31, 2018)
And the winner is ...
"I think Prochazka is a big problem, because of his pace, his chin and his heart," said Muhammed Lawal, coach at American Top Team. "His weakness would probably be cage work, because he spent so much time in Japan fighting in a ring. I feel like if Reyes is smart, he'll put him against the cage. The thing is, Jiri is so long and in good condition, throws a lot of punches and kicks. It's going to be an interesting fight."
To see how several coaches break down this fight and predict the winner, go here.
How to watch the fights
Watch the entire card on ESPN2. Don't have ESPN2? Get instant access.
There's also FightCenter, which offers live updates for every UFC card.
Saturday's fight card
ESPN2/ESPN+, 10 p.m. ET
Dominick Reyes vs. Jiri Prochazka | Light heavyweight
Cub Swanson vs. Giga Chikadze | Men's featherweight
Ion Cutelaba vs. Dustin Jacoby | Light heavyweight
Sean Strickland vs. Krzysztof Jotko | Middleweight
Merab Dvalishvili vs. Cody Stamann | Men's bantamweight
Poliana Botelho vs. Luana Carolina | Women's flyweight
ESPN2/ESPN+, 7 p.m. ET
Randa Markos vs. Luana Pinheiro | Strawweight
Gabriel Benitez vs. Jonathan Pearce | Men's featherweight
Kai Kamaka III vs. TJ Brown | Men's featherweight
Loma Lookboonmee vs. Sam Hughes | Strawweight
Luke Sanders vs. Felipe Colares | Men's featherweight
Andreas Michailidis vs. KB Bhullar | Middleweight
Four more things to know (from ESPN Stats & Information)
1. Cub Swanson enters his co-main event against Giga Chikadze on a two-fight win streak after having lost his previous four fights. He has 12 wins in the UFC at featherweight, giving him the third most in division history behind Max Holloway (17) and Darren Elkins (14). Chikadze went 4-0 in 2020, making him one of just two UFC featherweights ever to go 4-0 in a calendar year. The other was Holloway in 2015.
2. Ion Cutelaba, who faces Dustin Jacoby in another light heavyweight bout, lands 5.1 significant strikes per minute, the highest rate among all active UFC 205-pounders. But he is on a two-fight losing streak, while Jacoby has won two in a row.
3. Sean Strickland and Krzysztof Jotko will meet in a clash of middleweights on three-fight winning streaks. Jotko leads all active 185-pounders in takedown defense (87.1%) and has the third-most total strikes landed (1,014), trailing only Kevin Holland (1,195) and Derek Brunson (1,015).
4. Merab Dvalishvili, who faces Cody Stamann, is on a five-fight winning streak. He has 41 takedowns, the most of any active UFC bantamweight, and has the second-highest control time percentage (44.5%).
ESPN's Jeff Wagenheim contributed to this fight preview.