DENVER — Losing the worst-played major-league baseball game in this millennium was bad enough, but the Cincinnati Reds lost more than that — pending a medical work-up today of pitcher Johnny Cueto.

The Reds lost an almost indescribable game to the Colorado Rockies, 4-3, in 12 innings, but the real news happened about 3 1/2 hours before Rockies utility infielder Omar Quintanilla hit a walk-off home run against Mike Lincoln.

That's when Cueto walked into the dugout after the third inning and said his elbow hurt. He was immediately removed.

Some thought equal parts of thin air and thin defense put quick closure on Cueto's start in Coors Field Sunday afternoon.

Unfortunately for the Reds, it was something more sinister that knocked him out — soreness in his triceps tendon.

Cueto, making his 27th start, returned to Cincinnati on owner Bob Castellini's private jet for a full evaluation today, but early indications are that the 22-year-old rookie may be shut down for the season.

The 22-year-old Dominican didn't give up a hit in his three innings, but he was forced to throw 74 pitches because his teammates made three errors in the first two innings and he walked three.

"He came in between innings and said he was developing some stiffness and soreness in the back of his elbow," said trainer Mark Mann. "That's right where the triceps tendon comes into the elbow. Johnny being as young as he is, at this point of the season, logging as many innings as he has (155), we want to err on the side of caution, take no chances."

And there was another perplexing situation in the ninth inning with the Reds leading, 3-2. It was closer time, Francisco Cordero time.

Instead, David Weathers walked to the mound and gave up an unearned run that tied the game as the Reds made two errors. Weathers committed a balk to put the tying run at second, plus he gave up a walk and two hits.

"Cordero had to leave and go home due to a personal matter," said manager Dusty Baker. "We hope he'll be back with us in Houston."

As far as the game goes, it was the Reds falling out of an ugly tree and hitting every branch on the way to the ground.

They made as many errors (five) as they had hits (five), they struck out 14 times. They walked nine Rockies, threw two wild pitches, committed a balk, perpetrated a passed ball and Corey Patterson made his daily baserunning blunder by getting picked off base.

The videotape is going to Cooperstown as one of the five worst professional baseball games ever played.

Colorado stranded 18 and was 0 for 16 with runners in scoring position. Sound familiar? One difference. The Rockies won.

The game details are right out of a Dean Koontz novel. Scary.

Colorado took a 1-0 lead in the first when the Reds made two errors. First baseman Joey Votto kicked a ground ball, then Cueto walked two to fill the bases. Garrett Atkins blooped one down the right field line and right fielder Jay Bruce ran a long, long way. But he didn't need to dive and the ball skidded off his glove for an error a run.

The Reds tied it in the second on Votto's double and a single by Edwin Encarnacion.

Cueto left after three, replaced by Nick Massek, who pitched two scoreless innings while the Reds took a 3-1 lead, scoring one in the fifth on Paul Bako's sacrifice fly and one in the sixth on Chris Dickerson's third home run.

The Rockies pulled to within 3-2 in the seventh when Matt Holliday led with a single off Jeremy Affeldt, then stole second and third and scored on a wild pitch.

Then came Weathers in the ninth and Holliday reached on second baseman Brandon Phillips' error on a ball that ticked off Weathers' glove. Weathers was called for a balk, moving Holliday to second.

He scored on a single by Atkins on which Bruce was given an error on his throw home.

Meanwhile, the Reds didn't score from the sixth inning on and managed only one hit, Encarnacion's two-out single in the 11th.

"We gave 'em the first three runs on errors and didn't get a hit after the sixth inning," said Baker. "Doing that and making five errors (season's high) makes it awfully hard to win a game.

"We just can't get the big hit with runners on base, especially with two outs," he said. "It has been haunting us all year and we are just not a very good team at that part of the game."