Layne impressed late last season, posting a 3.24 ERA in 26 appearances. As it stands now, Joe Thatcher is the lone left-hander in the bullpen.
Blanks had one of the best performances of the spring, hitting .354 in 65 at-bats. He had three home runs and 14 RBIs.
"In Kyle's situation, he's got to establish himself again as a durable player, and he's got to play," said Padres manager Bud Black.
"His seasons have been interrupted due to injury. But he's very capable of being a good Major League player."
Black also confirmed that right-handed pitcher Tyson Ross will be the No. 5 starter in the rotation and will pitch on April 6 in Colorado.
Andrew Cashner, another candidate for the No. 5 spot in the rotation, has made the team as a long reliever, though the organization still wants him to become a starter.
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.