One bit of news took the Cincinnati Reds from their season high point to a new low: They have to try to hold onto first place without Joey Votto.

The Reds had their six-game winning streak snapped on Monday night shortly after learning they'll be without their best hitter for up to a month. Miguel Montero drove in four runs, and the Arizona Diamondbacks ended the Reds' surge with a 5-3 victory.

All that seemed secondary to worries about a future without the 2010 NL MVP.

Shortly before the game started, the Reds got MRI results showing Votto has torn cartilage in his left knee and will be out for three to four weeks.

''He's an MVP, a Gold Glover. What more can you ask in a guy?'' said Todd Frazier, who filled in at first base. ''Injuries are huge in baseball. He's got that presence. Whenever he is out there, he can do damage.''

Votto hurt his left knee while sliding on June 29, but kept playing because he didn't think the injury was severe. He started for the National League in the All-Star game on Tuesday, and played all three games of a sweep over the St. Louis Cardinals that left Cincinnati alone in first place in the NL Central.

He didn't have an MRI until Monday because he didn't think he needed one.

''He didn't request it until then,'' general manager Walt Jocketty said. ''He said it wasn't a problem until the last couple of days.''

Votto will have surgery on Tuesday, costing the Reds their top hitter. Votto is batting .342 and leads the NL in doubles, walks and extra-base hits.

Bronson Arroyo saw Votto before the game and got the bad news directly.

''He looked funny,'' Arroyo said. ''I said, `Are you playing?' He said, `No, I need surgery.' At this time of year, if we can keep pressure on the other teams in our division and stay in the race -- if we can weather the storm -- he could give us a lift when he comes back.''

Things didn't go so well in their first game without him.