From Danny Knobler (CBS Sportsline)'s blog:

Also claimed, according to sources, was Astros shortstop Miguel Tejada. The claiming team isn't known, but also isn't important, because the Astros have already pulled Tejada back and now can't trade him. Tejada is making $13 million this year, on the final year of his contract.

The Rays aren't believed to be the team that blocked Tejada, but sources said that Tampa Bay has been active in claiming any low-salary players, effectively blocking them from being traded to the Yankees or Red Sox.