Kapler (right hip flexor strain) spent the weekend playing for Class A Charlotte, and he will be with the team for Wednesday night's game against the Red Sox.
Blalock handled the news with class and professionalism.
"I try not to think about possible roster moves that might happen in the future," Blalock said. "If you think like that, then you're not being a good teammate for that day. So everyone knew that Kap was getting ready to come off the DL, and they told me that I was going to be the one the roster move was made for.
"Hopefully there will be a team that wants me to play for them. ... I'm not sure how the designated for assignment or released thing works out, or whatever. I'll fly back to Tampa and pack my stuff up and go be with my family in San Diego, and we'll see if there's another team that wants me."
Blalock has spoken on several occasions about how much he enjoyed playing alongside the group of players the Rays have on their roster.
"This is such a high-energy team, and there's so much emotion on this team that this team is capable of winning the World Series," Blalock said.
Blalock saw limited duty, hitting .254 with a home run and seven RBIs in 63 at-bats for the Rays.
"Every part-time player wishes he could play on a more consistent basis," Blalock said. "But my role that was explained to me when they brought me up [from Triple-A Durham] a couple of months ago was that I was going to be a part-time DH kind of thing. So I kind of just accepted that, tried to do whatever I could to help the team win when I was in there. That's it."
Rays manager Joe Maddon called Blalock "a real pro."
"I thought he did a great job for us in our clubhouse," Maddon said. "His work ethic is spectacular. And I really wish I had a longer time to work with this fellow, because he's really an interesting young man and he works and he really loves to play this game. The at-bats weren't going to be there and the opportunities weren't going to be there, and that's unfortunate. But he made a really good impression on all of us."