Ailin Perez’s ultimatum puts Macy Chiasson’s Mexico City bout on the brink — weight problems threaten the card

Who feels it first: fighters, matchmakers and fans. ailin perez has made a public ultimatum that shifts the immediate pressure onto Macy Chiasson, the Season 28 winner of The Ultimate Fighter, and onto UFC Mexico City’s weigh-in process for the Feb. 28, 2026, card at Arena CDMX. The decision to stand down if an opponent misses weight can remove a marquee bantamweight tilt and force last-minute logistical scramble.

Ailin Perez’s stance increases consequences for Chiasson, officials and the event

Perez’s refusal to accept a catchweight or to proceed if Macy Chiasson misses weight changes the dynamic from routine weigh-in drama to a true ultimatum. That stance affects three immediate groups: Chiasson (who faces questions about making bantamweight limits), event officials (who now must guard the scale closely), and fans expecting a ranked matchup on the Mexico City card. Here's the part that matters: a single missed scale can cancel the fight entirely rather than trigger the usual penalty or catchweight arrangement.

What was said and how the warning landed

Perez declared she doesn’t see Chiasson beating her in any area and warned she will not fight if Chiasson fails to make weight. In her comments she noted Chiasson’s recent weight issues and referenced past bouts where weight shortfalls led to catchweights. Perez also emphasized she prepared for three months to both make weight and compete, and that she sees Chiasson frequently at the UFC performance center and believes Chiasson looks "very big. " Perez added that she didn’t want this opponent because she found the matchup "boring and ugly, " and she suggested a finish is coming, pointing back to a prior finish in France.

Matchup snapshot and momentum

Macy Chiasson enters with a 10-5 record and arrives off back-to-back defeats to Yana Santos and Ketlen Vieira. Ailin Pérez comes in at 12-2 with five straight UFC wins, including victories over Karol Rosa, Darya Zheleznyakova and Joselyne Edwards. Chiasson’s size — listed as a 5-foot-11 frame in the context — plus a long jab, teeps and past finishes of Mayra Bueno Silva and a submission of Pannie Kianzad are part of her toolkit. Perez’s recent run features chained takedowns, heavy top control and relentless clinch work that has worn opponents down.

Weigh-in history, catchweights and the immediate trigger

Chiasson’s track record with the scale is detailed: she has officially missed weight twice in the organization and required catchweight bouts on two other occasions. Perez highlighted that Chiasson did not make weight for her last fight and the one before that, and that one of those catchweight bouts was with Ketlen Vieira. With Perez refusing to accept another miss, officials may be forced into difficult decisions at makeweight time.

• Feb. 28, 2026 — Chiasson vs. Perez scheduled for UFC Mexico City at Arena CDMX.
• Chiasson enters the bout after consecutive losses to Yana Santos and Ketlen Vieira.
• Perez arrives on a five-fight UFC winning streak with recent wins over Karol Rosa, Darya Zheleznyakova and Joselyne Edwards.

What's easy to miss is how much a single weigh-in can cascade into broader consequences for a fighter’s momentum and for the fight card as a whole.

Quick takeaways

• Perez’s ultimatum raises the odds of a canceled bout rather than a late catchweight accommodation.
• Chiasson’s recent back-to-back defeats and repeated scale issues increase pressure on her camp and performance center routines.
• Event officials will face heightened scrutiny at the weigh-ins; enforcement will determine whether the fight proceeds.
• Stylistically, Perez’s wrestling and clinch pressure contrasts with Chiasson’s length and finishing history — the matchup hinges on who controls the range and tempo.
• The real question now is whether a pre-fight weight resolution happens or whether Perez’s stance ends the fight before it begins.

Editor’s note: this piece stays grounded in stated comments and known records; if details about the weigh-in outcome or a change in either fighter’s status emerge, those updates may alter the practical stakes for both competitors and the event.