There are questions that Andre Berto must answer following his brutal loss to Robert Guerrero last November.

Berto (28-2, 22 knockouts), once one of the brighter stars in the welterweight division, absorbed a lot of punishment in two of his last three bouts – 12-round decision losses to Guerrero and to Victor Ortiz in 2011. The 29-year-old boxer-puncher also had to deal with an arm injury and the stigma of failing a pre-fight drug test (which postponed and then canceled his rematch with Ortiz last year), as well as inactivity (he’s only fought three times in the past 2¾ years).

It’s only natural for fans to wonder if the former titleholder – who left longtime trainer Tony Morgan for Virgil Hunter following the Guerrero fight – will ever regain his form and career momentum. The boxing media wouldn’t be doing their jobs if they didn’t ask if Berto still has the ability and desire to be a player in the 147-pound division.

Luckily for us, those questions will be answered in a boxing ring tonight. That’s because Berto will face Jesus Soto Karass, one of the sport’s more reliable gatekeepers, in the Showtime-televised main event of a Golden Boy Promotions card at San Antonio’s AT&T Center.

The gatekeeper’s job is to let boxing fans know who has real promise in a particular division and who doesn’t. Soto Karass (27-8-3, 17 KOs), a well-traveled 12-year veteran from Los Mochis, Mexico, has been a good litmus test for welterweight hopefuls (while giving fans good scraps) over the past six or seven years.

The rugged 30-year-old slugger let Mexican prospect Michele Rosales know that he was just an opponent on this side of the border by stopping the then-undefeated up-and-comer in 11 rounds in 2006. Soto Karass kept tough fringe contenders like Chris Smith, David Estrada and Carson Jones out in “the fringes” with hard-fought victories in 2008 and 2009.

And even when he dropped a close majority decision to Mike Jones in 2010, Soto Karass let fans know that despite an impressive physique and glossy record, the Philadelphia native was not the Heir Apparent to the welterweight division.

In recent months, Soto Karass let fans know that under Robert Garcia’s guidance, Marcos Maidana – who stopped him in the eighth-round of a slugfest last September – could be player at welterweight. He rebounded with a decision victory over Selcuk Aydin in January, letting fans know that the once-beaten Turkish Olympian is definitely not top-10 contender material.

Is Berto still top-10 contender material? We’ll find out. If he can’t beat Soto Karass impressively, his name will be added to the list of reliable gatekeepers in each of boxing’s 17 divisions below.

Heavyweight – Tony Thompson and Dereck Chisora. Thompson is recognized as the No. 9-rated contender by THE RING, but more than few members of the magazine Ratings Panel view the 41-year-old American southpaw as a gatekeeper, one who has rejuvenated his career with back-to-back stoppages of ballyhooed British prospect David Price. Prior to exposing chin and stamina weaknesses in the 2008 Olympic bronze medalist, Thompson was best known for losing two title shots to champ Wladimir Klitschko and beating back the advances of such heavyweight hopefuls as Lujan Krasniqi and Chazz Witherspoon. He’s scheduled to face unbeaten contender Kubrat Pulev on Aug. 24.

Chisora is the quintessential gatekeeper. He’ll probably never earn legit contender status but he’ll let fans know who really belongs among the top-10 big men of the sport. The 29-year-old Londoner recently dashed unbeaten American fringe contender Malik Scott’s hopes of cracking the top 10 with a controversial sixth-round stoppage. Prior to the Scott fight, “Del Boy” shed light on a number of name heavyweights by losing to them in different manners. Chisora let fans know that David Haye, who stopped him in five rounds, is still a player in the division. He let them know that WBC beltholdder Vitali Klitschko, who he went the distance with, can still fight but is getting old. He let them know that Robert Helenius, who earned a dubious decision over him, was overrated. And he let them know that Tyson Fury, who legitimately outpointed him, is more than just a big body and mouth.

Also: Dominick Guinn, Michael Grant, Danny Williams

Cruiserweight – Firat Arslan. It’s unlikely that the 42-year-old contender (rated No. 8 by THE RING) will beat longtime WBO beltholder Marco Huck in their rematch on Sept. 14, but the muscular veteran is strong and determined enough to test or beat any 200-pound up-and-comer, as he did to a trio of Russian badasses – Vadim Tokarev (draw), Grigory Drozd (TKO 5) and Valery Brudov (SD 12) – on his way to earning the WBA belt (against recent hall of fame inductee Virgil Hill) in 2007. Arslan held contender Alexander Alekseev to a draw last May before giving Huck spirited 12-round tussle.

Also: Troy Ross, Felix Cora Jr., Garrett Wilson

Light heavyweight – Denis Grachev. The former kickboxing standout from Russia looked like he was on his way to solid contender status with his impressive upsets over undefeated (17-0) hot prospect Ismayl Sillakh (TKO 8) last April and unbeaten (33-0) former lineal champ Zolt Erdei (SD 10) in March, but his recent first-round knockout loss to super middleweight contender Edwin Rodriguez nipped that notion in the bud. Grachev, who looked good taking former 168-pound titleholder Lucian Bute the 12-round distance last November, is a gatekeeper – and darn good one.

Also: Allan Green, Ovill McKenzie

Super middleweight – Brian Vera. The hardnosed Texas slugger is a tried-and-true gatekeeper at super middleweight, where he will face former WBC 160-pound titleholder Julio Cesar Chavez Jr. on Sept. 7, and at middleweight, where he recently bested two former junior middleweight beltholders – Sergio Mora (MD 12) last August and once-beaten (37-1-1) Sergei Dzinziruk (TKO 10) in January.

Also: Arthur Abraham, Don George, Don Mouton

Middleweight – Marco Antonio Rubio. Between title bout losses to Kelly Pavlik (TKO 9) and Chavez Jr. (UD 12), Rubio stopped two undefeated prospects – most notably popular Canadian puncher David Lemieux (TKO 7) in April of 2011 – during a 10-0 run. Since the loss to Chavez, the heavy handed-but-wily Mexican veteran has won four in a row (and will likely extend his streak to 5-0 when he faces shopworn Dionisio Miranda tonight) including a stoppage of then unbeaten (12-0) Mexican prospect Jorge Cota.

Also: Vera, David Alonso Lopez, Saul Roman, Kassim Ouma, Ossie Duran

Junior middleweight – Saul Roman. The 33-year-old Mexican veteran has been campaigning at middleweight, where he’s won his last three bouts and will face New York puncher Curtis Stevens on Aug. 3 (he’s fought as heavy as 168 pounds where he lost to Thomas Oosthuizen in 2010), but the game slugger earned his gatekeeper status at junior middleweight, where he gave Vanes Martirosyan (who he dropped before being stopped in the seventh round) and Gabriel Rosado (who narrowly outpointed him) fits in losing efforts.

Also: Ouma, Duran

Welterweight – Soto Karass. Our “cover boy” for this feature was upsetting the applecart as early as 2002, when blasted future fellow gatekeeper Saul Roman (then 9-0) in one round. After dropping three consecutive decisions to undefeated prospects, Soto Karass gained fringe contender status by going unbeaten during a 15-bout stretch that was snapped by Alfonso Gomez in November of 2009. He’s lost as much as he’s won since dropping that technical decision to The Contender star, but few have had an easy night with him.

Also: Alfonso Gomez, Julio Diaz, Ashley Theophane, Freddy Hernandez

Junior welterweight – DeMarcus Corely. It seemed like the 39-year-old former WBO titleholder was headed for Palookaville by the end of 2011, after he’d lost six consecutive bouts (mostly to card carrying badasses such as Lucas Matthysse and Maidana), but the ring savvy southpaw rebounded with back-to-back upsets over Gabriel Bracero (UD 10) and Paul McCloskey in 2012, saving his gatekeeper status. Despite dropping a 12-round decision to Viktor Postol last October, many fans liked Chop Chop’s chances of upsetting Frankie Gomez before the young prospect pulled out of their July 20 match with an injury.

Also: Hank Lundy, Breidis Prescott, Nate Campbell, Ricardo Williams Jr., Kaiser Mazbuza

Lightweight – Jose Hernandez. Ask hardcore fans who watched Hernandez’s fights with the then-unbeaten trio of lightweight prospects Michael Perez, Mickey Bey and Luis Ramos Jr. and most will tell you the 26-year-old Texas native won them all. Alas, Hernandez had to settle for razor thin decision losses (majority with Perez; split with Ramos) and a draw (with Bey). However, the tall Texas slugger took the judges out of the equation when he scored an eighth-round TKO of undefeated Canadian standout Tony Luis in January. Hernandez faces fellow gatekeeper Rustan Nugaev on Aug. 8.

Also: John Molina, Nugaev, Miguel Acosta, Ji-Hoon Kim, Walter Estrada

Junior lightweight – Alejandro Perez. The Salinas, Calif.-based boxer-puncher was a solid junior featherweight prospect outclassed by future titleholder Rico Ramos in 2009. However, after sitting out 2010, Perez returned to the ring as a dangerous 130 pounder, who shocked Antonio Escalante with a first-round stoppage and dominated spoiler Derrick Wilson before and after dropping a 10-round decision to top-10 contender Diego Magdaleno. He followed the Wilson victory with a 10-round decision over unbeaten (15-0-2) fringe contender Art Hovannisyan.

Also: Edner Cherry, Edgar Puerta

Featherweight – Robinson Castellanos. The 31-year-old veteran lost eight of his first 13 bouts – including a fifth-round TKO to current RING champ Mikey Garcia in 2008 and a split decision over former bantamweight beltholder Julio Zarate in 2009 – but the durable Mexican has only lost one of his last 13 bouts and is currently on a 10-bout win streak that includes decisions over undefeated (19-0) Christopher Perez and, in his most recent bout in April, two-division beltholder Celestino Caballero.

Also: Bernabe Concepcion, Rafael Marquez, Perez

Junior featherweight – Hugo Cazares. The 35-year-old former junior flyweight champ and 115-pound beltholder is ancient for the sub-featherweight division, but the switch-hitting banger is still punching and still a threat now that he’s campaigning at junior featherweight, where he’s won four in a row – including a decision and first-round KO over young Filipino standouts Rey Perez and Gabriel Altarejos.

Also: Fernando Montiel, Raul Hirales

Bantamweight – Rolly Lunas (AKA Matsushida). The current OPBF champ has lost to some very good fighters over the years, including WBA titleholder Anselmo Moreno, but is currently on a respectable six-bout win streak that includes an 11th-round TKO of current Japanese champ Kohei Oba. The 29-year-old Filipino veteran also has a 2007 technical decision over current top-five contender Malcolm Tunacao.

Also: Tomas Rojas, Christen Esquivel, Alvaro Perez, Ronald Barrera

Junior bantamweight: Juan Jose Montes. The young Guadalajara native fell short in a 2011 challenge to then-WBC beltholder Tomas Rojas, but has since notched two victories over veteran Oscar Ibarra and held future bantamweight title challenger Victor Zaleta and former flyweight beltholder Julio Cesar Miranda to draws.

Also: Richie Mepranum, Rodel Mayol, Fernando Lumacad, Edrin Dapudong

Flyweight: Sonny Boy Jaro. Despite the Filipino veteran’s shocking RING/WBC title-winning TKO over Thai legend Pongsaklek Wonjongkam last March, he’s a gatekeeper. The 31-year-old will continue to give talented flyweights tough fights as he did Toshiyuki Igarashi, who relieved him of the 112-pound championship last July.

Also: Ricardo Nunez, Silvio Olteanu, Sammy Gutierrez

Junior flyweight: Alberto Rossel. The 35-year-old veteran is THE RING’s No. 10-rated contender but he usually loses when he steps up his competition and when he travels outside of his native Peru. However, Rossel’s won six in a row since being stopped in the ninth round of a WBA title bout vs. Hugo Cazares. His current streak includes a 12-round decision over then-unbeaten (28-0) prospect Jose Alfredo Rodriguez.

Also: Gilberto Keb Baas, Mario Rodriguez

Strawweight: Pornsawan Porpramook. The relentless Thai veteran has lost five out of six title shots but has given every beltholder he’s fought hell, and he’s pretty much beaten everyone else he’s fought.

The 35-year-old slugger’s see-saw 10^th-round TKO loss in a failed WBA title defense against current RING flyweight champ Akira Yaegashi was a 2012 Fight of the Year candidate.

Also: Jetly Purisima, Karluis Diaz

Photos / Naoki Fukuda, Scott Heavey-Getty Images, Tom Casino-SHOWTIME, Nick Laham-Golden Boy, Richard Wolowicz-Getty Images, Luis Acosta-AFP

Anson Wainwright contributed to this feature.