Tejada played in Baltimore for four years before being traded to Houston in December 2007. The trip will mark his first time in Maryland since his relocation.
The shortstop said he is eagerly anticipating the visit with old teammates and friends.
"I'm happy to go back," Tejada said. "Everybody up there is my friend. I look forward to seeing all those people, because I was used to seeing them every day. I want to say hi to all those people."
Tejada expects the welcome from his former teammates to be warm, but the fans might be a different story.
He had asked the Orioles to trade him in the two seasons before his eventual departure, saying he wanted to play for a team that would help him win. Though it took two years, the O's finally complied, getting five players in return for the 2005 All-Star Game Most Valuable Player.
"I'm not really concerned with how [the fans] respect me," Tejada said. "I don't play for them anymore. The fans there are first-class, and it doesn't matter what they're going to do. If they boo me or don't boo me, they are still one of the best clubs to play for, and I really appreciate the time I had there."
There should be no bad blood, Tejada said, because he had not asked for the trade the year Baltimore made the move.
The Orioles got pitchers Matt Albers, Troy Patton and Dennis Sarfate, outfielder Luke Scott and third-base prospect Michael Costanzo in the deal.
"I think the best thing for the team was for me to go somewhere else and for the team to get what they got," Tejada said. "They should be happy with what they got."
Cooper said he knew nothing about Tejada before he arrived in Houston in December.
He had never seen the 2004 Home Run Derby winner play, but he was pleased with what he got.
"He's been a real solid player for us and a lot better than I expected," Cooper said. "They're all going to have little slumps here and there, and he's had a few skids here the last few weeks, but other than that, he's played well."
Tejada is batting .300 with nine home runs and 41 RBIs this season. Although he has struggled a bit in June -- he has had only four RBIs and his average has dropped 17 points -- he was in the lead in National League All-Star shortstop balloting earlier this month.
Tejada and the Astros take the field at 6:05 p.m. CT on Tuesday against his old teammates.
"It will be a little bit weird the first time," Tejada said. "It has only been a year since I played for that team. It's not the first time that I played for another team. I used to play in Oakland, and the first time [I played there] was a little bit hard. For me, though, it will be OK."