Harrison (back) will pitch in an extended spring training game Wednesday, after throwing 45 pitches of live batting practice Thursday, Jeff Wilson of the Fort Worth Star-Telegram reports. The Rangers are being cautious with Harrison, who could start a rehab assignment by the end of May. He's seemingly on track to join the big-league rotation in early-to-mid June, although it isn't clear which starter he'll replace. Ross Detwiler is the leading candidate thus far, but he still has some time to make up ground on Wandy Rodriguez, and it's quite possible one of the Rangers' current rotation members will be injured by the time Harrison's ready.