Ankle ligaments. The most buzz-worthy storyline for Mexico and U.S. fans ahead of October’s playoff between the two nations for CONCACAF’s 2017 Confederations Cup berth has revolved all around ankle ligaments; specifically, left ankle ligaments. And more specifically, the left ankle ligaments of Andres Guardado.

Ever since the reigning Gold Cup Most Valuable Player, clearly the best player for Mexico at the tournament El Tri won to force this one-off, limped off in PSV’s Champions League victory over Manchester United, fans and press on both sides of the border have been anxiously awaiting updates about the 28-year-old’s status. The diagnosis came down Monday, and it’s not looking good for Guardado.

The first thing for American fans to note before they start celebrating is that Mexico hasn’t ruled out the possibility of Guardado recovering in time for the playoff. The Mexican national team sent kinesiologist Carlos Pecanha over to the Netherlands to help rehab and hopefully recover more quickly than the four-to-six week time table his club offered.

SEE MORE: CONCACAF releases US, Mexico preliminary squads.

It’s not just hopeless optimism. Little has come out about the specifics of Guardado’s injury, and even if we knew more, even the medical community isn’t always well-educated on the topic. “Despite the fact that the ankle ligaments are prone to injury during the vast majority of sports, literature focusing on the ankle ligaments is rare,” Pau Golanó writes in a paper published in the journal Knee Surgery, Sports Traumatology, Arthroscopy.

Skipping the literature and reading the tea leaves, there’s a very good chance Guardado isn’t good to go, something that would be big blow for interim Mexico manager Ricardo Ferretti. “Tuck” now faces not only the question of who to play in Guardado’s absence but the possibility of an entire formation switch.

After trying his preferred 4-4-2 against Trinidad and Tobago and getting a hard-fought 3-3 draw, Ferretti went with Mexico’s familiar 5-3-2 against Argentina to much-improved results, albeit in another stalemate. Guardado is a versatile player who has seen time at fullback for club and country but found a home on the left side of the Mexico attack, coming inside to shore things up when Miguel Layun pushes forward from his wingback spot.

But the 5-3-2, with Guardado on the left of a midfield also including Jose Juan “Gallito” Vazquez and Hector Herrera, seemed most likely for next month’s clash in Pasadena. Ferretti could try to keep the formation the same, but he might be better served switching back into a four-man midfield, especially with the possibility center back Rafa Marquez may also miss the playoff with an injury.

SEE MORE: What Tuca Ferretti learned from his first friendlies.

The first option on the left side is Javier Aquino. Ferretti brought Aquino into his club team, Tigres, during the offseason and slotted him into the Mexican team in the friendly against Trinidad and Tobago. Aquino has some speed and vision but is nowhere near the defender Guardado is and might be a risk to play in front of a left back that likes to take chances like Layun.

Another intriguing option is Toluca’s Carlos Esquivel. The midfielder played in the center of the midfield in that match against Trinidad and Tobago but has also seen time as a winger since Miguel Herrera revived his national team career. Esquivel also has history with Ferretti, playing with Tigres in 2008. Defensively, he’s stronger than Aquino, but he doesn’t have the speed to trouble back lines the way other weapons at Ferretti’s disposal do.

Another option is Jesus “Tecatito” Corona, who is a natural winger, though he’s seen more time at forward since his summer move to Porto. Corona is very shifty and can go into his bag of tricks to take on defenders one-on-one. Getting the ball into the box hasn’t been his strength, but the 22-year-old was Mexico’s most creative player at the Copa America this summer and earned Best Young Player honors at the Gold Cup. He’s shown he can raise his level of play and wouldn’t be cowed by the playoff occasion.

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The real linchpin in the discussion is Jonathan dos Santos. The Villarreal midfielder might have been the best player not named Guardado in Mexico’s Gold Cup side, but he was left off Ferretti’s September squad. The reasons for that omission remain a bit opaque. While Jona does all right getting forward, he’s far better suited to play in the center of the park, with a pairing next to Gallito an enticing possibility. Even manning the central spot solo, as he did during the Gold Cup, is an option. Of course, that’s if Ferretti even plans to name him to his final roster and utilize him at all.

There’s no doubt that Guardado’s injury demands Ferretti make a tough decision about how he aligns his team, but there’s also little doubt that he has options that aren’t a horrific drop-off in quality. Whatever he chooses won’t escape scrutiny, but will provide far more chatter than ankle ligaments in the build up.