The Texas Rangers are sending struggling rookie outfielder Michael Choice to Triple-A Round Rock and preparing to use their 12th starting pitcher this season.
Choice, who had a .177 average with eight homers, was demoted and infielder Donnie Murphy was designated for assignment Monday.
The Rangers brought up right-handed reliever Roman Mendez and outfielder Jake Smolinski from Round Rock, and both had a chance for their major-league debut in the series opener against Houston.
Rookie right-hander Nick Martinez was scratched from Tuesday's start because of discomfort in his back. He will be replaced by right-hander Phil Irwin, who made his only big-league appearance in a start for Pittsburgh last year.
The Rangers have 10 days to trade, release or outright Murphy to the minor leagues. He was hitting .196.