The Nationals released Castillo last week, Kyle Glaser of Baseball America reports.

Castillo signed a minor-league contract with the Nationals on Thursday, Jesse Dougherty of The Washington Post reports.

Castillo signed with the NPB's Tohoku Rakuten Golden Eagles on Saturday.

Castillo (groin) will start in right field Sunday for in Triple-A Pawtucket's game against Syracuse.

The Red Sox assigned Castillo (groin) to their minor-league camp Tuesday, Alex Speier of The Boston Globe reports.

Castillo was named the International League Player of the Week, Alex Speier of The Boston Globe reports.

Castillo has been invited to the Red Sox's major-league camp this spring, Evan Drellich of NBC Sports Boston reports.

Castillo (groin) was activated off the 7-day disabled list and reinstated to Triple-A Pawtucket. He went 4-for-20 over five games played since being activated.

Castillo will be placed on the 7-day disabled list with a groin strain, Alex Speier of The Boston Globe reports.

Castillo left Wednesday's game with groin tightness, Mark Daniels of the Providence Journal reports.