MIAMI (AP) _ It was a long night for the Detroit Lions, and a short night for Cecil "the Diesel" Collins.

The Miami Dolphins' rookie running back severely sprained his right ankle early in Saturday night's 31-10 exhibition victory over Detroit.

Collins, who had been challenging for the starting job, will be sidelined at least a few weeks, coach Jimmy Johnson said. There may be a slight fracture in the ankle, Johnson said, and Collins will undergo further examination Sunday.

Miami's Tony Martin, who was acquitted of laundering drug money by a federal jury Thursday, had five receptions for 67 yards. He caught a 5-yard TD pass from Dan Marino, one of just three scores by the first-team offense in 17 preseason possessions.

Dolphins fullback Stanley Pritchett sprained his left knee. Lions receiver Herman Moore bruised his right shoulder and sat out the second half.

The Dolphins' defense scored twice and set up another touchdown with interceptions.

Sam Madison gave Miami (2-1) a 7-3 lead when he picked off a pass by Charlie Batch and ran untouched 46 yards down the sideline for the score, high-stepping the final 20 yards.

The Dolphins' Jerry Wilson returned another interception to the Detroit 27, and Miami scored five plays later on Marino's pass to Martin for a 14-3 lead.

Patrick Surtain intercepted a pass by Gus Frerotte and returned it 40 yards for a score with 1:26 left.

Marino played three quarters and went 19-for-29 for 195 yards, by far his best game so far. Batch was 11-for-25 for 169 yards with three sacks and two interceptions.

Frerotte drove the Lions (1-2) 67 yards in the final quarter for their only touchdown, hitting Brian Stablein on a 3-yard scoring pass.

Kio Sanford scored for Miami on a 32-yard reception from Damon Huard.

The Dolphins' first-team offense went 0-for-3 in short-yardage situations, a problem last season. James Jones and Kelvin Pritchett stopped Karim Abdul-Jabbar for no gain on fourth-and-goal at the 1. Abdul-Jabbar also failed to convert an earlier fourth-and-1 and a third-and-1.

Jason Hanson put Detroit ahead 3-0 with a 53-yard field goal. He was short from 55 yards, his first miss in seven attempts this preseason.

Ron Rivers had a 33-yard run, but otherwise Detroit's ground game sputtered. Linebacker Chris Claiborne, the Lions' first-round draft choice, had eight tackles, one assist, two passes defended and a fumble recovery on a punt return.

Surtain recovered an onside kick in the fourth quarter. The Dolphins were called for interference on the play, but the penalty was overturned on a replay challenge and possession was awarded to Miami.