Denver Broncos quarterback John Elway partially tore his right biceps muscle during tonight's 38-19 preseason loss to the Miami Dolphins.

It wasn't apparent how Elway hurt his throwing arm, but he left during a timeout late in the first quarter.

"My biceps is partially torn," Elway said. "I'm not sure how I did it. We'll do an MRI tomorrow and it could be really good or it could be really bad. We'll have to wait and see."

"By no means is it a season-ending injury," Coach Mike Shanahan said. "He could be back as quick as one week, it could take three weeks. There's more pain than anything else."

The Dolphins, who have been devasted by injuries this preseason, suffered another one when middle linebacker Zach Thomas broke his leg. Hurt during a first-quarter kickoff, Thomas hopes to be back by the season opener.

Said Coach Jimmy Johnson: "I'm sick about Zach Thomas breaking his fibula but hopefully we'll have him back in three to four weeks."

Meanwhile, the NFL's latest foray south of the border was another big hit. A crowd of 104,209, the third largest in league history, turned out at this city's massive soccer stadium to cheer on the Dolphins, second favorite in Mexico only to the Dallas Cowboys, and even one of their countrymen.

The crowd sang and shouted throughout a damp and unseasonably cold night.

The fans chanted "Del-fines" when their beloved Dolphins did well. The Broncos had their share of supporters, but were booed all night. The crowd unleashed its loudest hoots and whistles when a Bronco took a knee in the end zone on the kickoff following the final touchdown.

The place went nuts when Dolphins rookie Brian Manning caught a pass from Craig Erickson at midfield and ran for a 66-yard touchdown early in the fourth quarter. Manning pleased the crowd in the second quarter when he extended at the goal line and pulled in an 18-yard pass from Dan Marino.

The one favorite on the Broncos (1-1) was Mexico City native Marco Martos, who was in the ninth day of a 10-day contract with the Broncos. A star in the World League, Martos drew a huge ovation when he lined up to receive the second-half kickoff. Flash bulbs blazed when he returned it 26 yards and the crowd went wild when he caught a pass in the final minute.

Martos is the first born, bred and schooled Mexican national non-kicker to play in the NFL. He drew bigger media exposure here this week than Elway and Marino combined, but is probably destined for another year in the World League.

Estadio Guillermo Canedo (formerly Azteca Stadium), was the site of the largest crowd to watch an NFL game, 112,376 in 1994, as Houston beat the beloved Cowboys 6-0 on a field turned to muck by torrential rain. Miami (1-1) was a clear winner in the apparel department, as thousands of fans wore Dolphins caps, jackets and Marino No. 13 jerseys. "The first team in the Mexican tradition is Dallas, and second is Miami," said Alfredo Rodriguez, 32, who attended with his three brothers, all wearing Dolphins jackets. The reason, he said, is "charisma and exposure."