Blalock has been almost exclusively a third baseman since he broke into the Major Leagues. He played four games at second base in 2003 but has never played first base. Blalock and club officials settled on the switch earlier this week when he decided his right shoulder just would not handle the strain of playing third down the stretch.
"That's my position the rest of my year," Blalock said. "I'll worry about the rest of my career later."
Blalock had been on the disabled list since July 28 with inflammation in the shoulder. He underwent surgery on May 21, 2007, and the shoulder has never really been at full strength since.
Blalock, who missed 2 1/2 months because of a torn left hamstring and then right wrist surgery, tried to play third base when he came off the disabled list at the All-Star break. But he lasted just nine games before the shoulder started acting up again.
He tried to come back as a third baseman but gave up on that idea before Texas decided to switch him to first base. That was the plan as far back as May, but that was before Davis was called up from Triple-A and provided an immediate impact with his offense.
"Coming off the All-Star break, I thought I would be able to play third base for the rest of the year, but that didn't happen," Blalock said. "Now, I want to finish the season strong. I'm excited to be back in the big leagues and playing with the guys. My body feels great, now I just want to go out and have some fun."
Blalock played in three games at Triple-A Oklahoma on a medical rehabilitation assignment before being activated. He went 6-for-12 with two doubles.
"I know if they throw one in the wrong spot, Hank will take a hack at it," manager Ron Washington said. "If they hit a ground ball at him, he'll catch it. If they throw a ball at him, he'll catch it and step on first. That's all he needs to do. Hank's a pro."
Davis has played two games at third base this season for the Rangers, but that was his position all of last year while in the Minor Leagues.
"After two days of working with Chris, he doesn't seem too rusty," Washington said. "If he has any difficulties, it might be on the slow roller, coming in, picking up the ball and getting rid of it quickly. But that might be the only problem. If they hit a ground ball at him, he'll certainly catch it."
Metcalf was hitting .214 with four home runs and eight RBIs in 16 games over three tours with the Rangers but was 9-for-26 (.346) in the last two weeks.