No elite NFL team has ever been more ripe for a beating than the Colts were at the Metrodome on Sunday.

Troubled defensive tackle Ed Johnson was booted off the team Wednesday. No. 1 tight end Dallas Clark (knee) was de-activated Sunday. And missing for the second consecutive game were the starting trio of center Jeff Saturday and guards Ryan Lilja and Mike Pollack.

Then things got ugly.

After the Vikings celebrated the second of five Ryan Longwell field goals, Colts left tackle Tony Ugoh suffered a groin injury with 4 minutes, 45 seconds left in the first half. The Colts trailed 6-0 and should have lost, but somehow won 18-15 with one regular starting offensive lineman, no running game and a pathetic defensive-tackle rotation that was mainly responsible for Adrian Peterson averaging 8.4 yards on 14 first-half carries.

Left guard Charlie Johnson replaced Ugoh. Rookie Steve Justice, a sixth-round draft pick who played center at Wake Forest, stepped in at left guard, making his NFL debut next to center Jeremy Richard, a rookie seventh-round draft pick.

"I got a few snaps at guard this preseason, but nothing much," Justice said. "The last time I played guard was my freshman year. But [offensive line] Coach [Howard] Mudd told me if something happened, I was next up. The way things have been going, something did happen."

The Colts' bad luck continued when safety Bob Sanders, their best run-stopper, was carted off the field because of an ankle injury with 10:46 left in the game and the Vikings leading 15-7. And yet Peterson gained only 27 of his 160 yards on seven attempts (3.9) with Sanders in the locker room.

Peyton Manning led the way, naturally. It was the 31st time in his 11-year career that he led the Colts from a fourth-quarter deficit or tie to victory. He completed eight of 15 fourth-quarter passes for 108 yards, including a 32-yard game-tying TD to Reggie Wayne and a 20-yarder to Wayne that set up Adam Vinatieri's game-winning 47-yard field goal with three seconds left.

"All wins are sweet and hard to come by," Manning said. "It's hard to rank them. Obviously, we've had a lot of good wins around here."

But few if any came with this many young players playing in their first or second NFL games. By game's end, the Colts were leaning heavily on four rookies, including tight end Tom Santi and undrafted defensive tackle Eric Foster.

Foster is only 6-2 and 265 pounds, but he got the call when the Colts released Johnson after an arrest on charges of speeding and marijuana possession. Johnson, the Colts' only player with typical size for an NFL tackle, had several run-ins with police while at Penn State. The Colts signed him as a rookie free agent last year with the understanding that he would be released after his first off-field problem.

"We didn't see it coming," Foster said of Johnson. "It's a shame, but like Coach [Tony] Dungy said all week, 'It doesn't matter who's not playing. It only matters who is playing.' "

The Colts became so thin after Ugoh's injury that they didn't even have a goal-line package to use when they reached the Vikings 1-yard line in the third quarter. They did score, but not until two sneaks by Manning were stuffed.

"Steve Justice is our third tight end in goal-line, and he's playing guard," Manning said. "We're at the half-inch line, and we're struggling to get it into the end zone. The injuries definitely affect you, but you just have to deal with it and find a way to make it work."

Mark Craig • mcraig@startribune.com