Supplemental first-round pick Keon Barnum is expected to miss six weeks after he had surgery on Monday.

Barnum, who signed a $950,000 bonus after the White Sox selected him 48th overall in last summer's MLB Draft, had surgery to remove the hamate bone from his right hand. The average recovery time for the injury is six weeks, a team official said.

This is the second time Barnum has been injured in his career; he was limited to 13 games last summer by a shoulder injury. Barnum hit three home runs in his first five professional games before the shoulder injury.

He is expected to open the season at Single-A Kannapolis.

Castro stays hot

Simon Castro, rated by Baseball America as the No. 20 prospect in the organization, struck out five batters and allowed a hit in two scoreless innings against the San Francisco Giants on Monday. In five innings this spring, Castro -- who came to the White Sox in a trade that sent Carlos Quentin to the San Diego Padres -- has struck out eight batters and allowed two hits.

“He’s thrown as good as we’ve seen him thrown,” pitching coach Don Cooper said. “Stuff is good, changing speeds. Velocity is good. Aggressive throwing strikes, all of the things we wanted anybody to do.”