CINCINNATI -- After he was scratched from Friday's lineup because of back spasms, Reds third baseman Todd Frazier was starting on Saturday against the Tigers.

Frazier did pinch-hit in the eighth inning on Friday and delivered a clutch game-tying RBI double to left field.

"I was swinging in the cages and the right side and middle muscles just tightened up. I couldn't really move," Frazier said on Saturday. "They worked on me. I give thanks to the training staff and everybody there that really helped me out. It feels a lot better today. I worked on it just now and I'm going to go swing. I feel good."

The Reds went on to beat Detroit in 10 innings Friday by a 6-5 score.

"I didn't feel it when I was swinging yesterday. The adrenaline was going," Frazier said. "I woke up today a little nervous, but I didn't feel anything. I was just a little sore. I'd rather have sore than pain. That's doable."

Votto swinging red-hot bat over past few weeks

CINCINNATI -- One of the best hitters in baseball is now one of the hottest in the game, and that can only mean tough times are likely ahead for pitchers that have to face Reds first baseman Joey Votto.

Entering Saturday, Votto had a career-best tying 14-game hitting streak but the numbers inside the streak are even more impressive. He came in batting .549 (28-for-51) during the stretch with three home runs and 10 RBIs. Among his three hits on Friday, Votto hit a three-run homer during the Reds' 6-5 win over Detroit in 10 innings.

"I felt really good lately," Votto said. "A lot of the stuff I was working on earlier in the season I was having trouble with, I think that I've cleared it up. You're always battling in this game to get back to neutral and in the past stretch I feel like I have been, but you can never explain when you go through these hot stretches why it happens. But it does and you enjoy and you continue to work to minimize the valleys and get yourself ready to work."

Over his past 13 games, Votto was batting .563, which was considered the highest average for a 13-game stretch since Gordy Coleman hit .571 for the Reds in May 1965.

Votto came into the day the Major League leader in doubles (25) and the National League leader in hitting with runners in scoring position (.422) and walks (46). His .360 average was second in the NL behind the Giants' Melky Cabrera.

Votto extended his hitting streak to 15 games while going 1-for-2 with two intentional walks during Saturday's 3-2 loss to the Tigers. In the fourth inning vs. Justin Verlander, Votto hit a double that skipped off of Delmon Young's glove in a sunny left field.

Known for being a cerebral hitter, Votto felt that most of the improvements and adjustments he made were mental.

"You're asking yourself to do the work behind the scenes for determination," Votto said. "For the stretches where you're just not doing anything, you go home and you almost want to cry sometimes and people don't understand that part of the game. But the determined ones generally realize that your success comes from work and from the intensity you use on the field."

Bray set to begin rehab assignment at Class A

CINCINNATI -- Left-handed reliever Bill Bray, who has been on the disabled list since April 24 because of left groin and back injuries, was slated to begin a rehab assignment at Class A Dayton on Saturday.

It was Bray's second attempt at a rehab assignment. He pitched one game for Triple-A Louisville before being shut down with back issues. He had been throwing lately at the team's complex in Goodyear, Ariz.

Even without Bray, Nick Masset and Ryan Madson, the Reds' bullpen entered Saturday leading the National League with a 2.43 ERA.

"Don't ask me what we're going to do," Reds manager Dusty Baker said. "You can never have enough pitching."

Bray is also scheduled to pitch for Dayton on Monday. His rehab assignment can last up to 30 days, so it's too soon to identify a role.

"I'll worry about that when he gets here," Baker said. "I want him to get well now vs. being worried about what he's going to do when he gets here. We want the Billy Bray that we know."

Worth noting

• Saturday's game vs. the Tigers marked the Reds' fifth sellout of the 2012 season. Great American Ball Park was also sold out for Friday's series opener.