By JEFF WILSON Welcome to the second half of the 2010 major-league season, which the Texas Rangers enter as possessors of the largest divisional lead in baseball and with the No. 1 hired gun in the game on their roster.They are considered to be the front-runners to win the American League West, and some oddsmakers have gone so far as to install them as the most serious threat to usurp the Yankees as world champions.Yet, the Rangers have only one playoff victory in their history and haven't been to the postseason since winning the AL West in 1999.Their most recent on-field performance saw them get swept over four games -- at home -- by the worst team in baseball.