White Sox's Luis Castillo acquisition has mostly been a disappointment

The Chicago White Sox's trade-deadline acquisition of starting pitcher Luis Castillo has mostly been a disappointment. 

Castillo struggled for the fourth time in five starts with one quality start for the White Sox. Reliever Seranthony Dominguez, whom the White Sox traded to Seattle for Castillo, has struggled with the Mariners.

In a 7-4 White Sox win at the Minnesota Twins on Friday night, Castillo pitched four innings, allowing four runs on eight hits, with one walk, one strikeout and two home runs allowed. The White Sox staked Castillo to a 4-0 lead in the top of the first inning. Minnesota scored three runs in the first and one in the second to tie the game.

The White Sox answered with one each in the third and fourth innings, but Castillo was pulled after four innings, making him ineligible to get the win. Hagen Smith, Grant Taylor and Bryan Hudson shut down Minnesota over the final five innings to lower the White Sox's magic number to 24.

Minnesota had four hits and struck out six times combined against Smith, Taylor and Hudson. Taylor improved to seven wins and two losses and Hudson earned his sixth save. 

Castillo has been unable to add depth to a White Sox rotation that desperately needs it.