Rangers' rotation concerns

The Texas Rangers have a solid starting rotation, led by right-hander Yu Darvish and southpaw Matt Harrison. After that, there are questions to be answered, including the durability of reliever-turned-starter Alexi Ogando and who fills in for Colby Lewis for a few months. The key, writes ESPNDallas.com's Richard Durrett, is left-hander Derek Holland, who reportedly is on a mission to focus more than ever before.