LHP Ben Kozlowski, who went from Single-A to two starts for the Rangers last season, is struggling at Double-A Frisco this season.
In seven starts, Kozlowski, 22, is 0-2 with a 6.75 ERA, and appears to have lost some velocity on his fastball. Assistant GM Grady Fuson says the team is not concerned about their prospect, noting that he will probably stay at Frisco most of the season.