Taken by the Sox with their top pick in the 2011 draft at No. 47 overall, Walker, 22, also had a small tear in his knee repaired. The switch-hitter is expected to be ready for spring ball.
Walker started the 2012 season with Low-A Kannapolis, where he hit .282/.395/.387 in 74 games, before earning a promotion to High-A Winston-Salem. The speedster saw his numbers drop a bit in the advanced league, and finished the season hitting a combined .267/.378/.379 with 22 doubles, four homers, 55 RBIs, 56 steals and 143 strikeouts.
Walker improved on his 2011 season, when he hit .257/.335/.320 while splitting time between rookie-level Great Falls and Kannapolis.