Rangers Designate Mark Hamburger For Assignment

The Rangers designated Mark Hamburger for assignment, Jeff Wilson of the Fort Worth Star-Telegram reports (on Twitter). The move clears a 40-man roster spot for Roy Oswalt, who joins the team tonight.

The Rangers acquired Hamburger from the Twins for Eddie Guardado in 2008. The 25-year-old right-hander appeared in five games for the Rangers last year and has spent this season at Triple-A, where he has a 6.55 ERA with 7.3 K/9 and 4.2 BB/9 in 45 1/3 innings.