If the Rangers have any lingering doubts as to whether Manny Ramirez is playing it clean in his comeback bid, they should soon know the answer thanks to a curiously timed random drug test during the slugger's first week with Triple A Round Rock.

A source said on Thursday that all players who weren't on the 40-man roster were subjected to a drug test earlier this week. Included in the group was Ramirez, who twice has failed tests for performance-enhancing drugs.

General manager Jon Daniels declined to comment on the timing of the test, but said that the word from Round Rock indicates that Ramirez, 41, has been a model citizen after signing a minor-league contract last week with no guarantees of getting a promotion to the Rangers' roster.

"The reports have all been very positive," Daniels said. "The guys say he's been in the cage early and often, and generally has been a good influence."