The 21-year-old right-hander had surrendered eight earned runs over 9 2/3 innings in his first three appearances but allowed only three baserunners in matching his longest outing since signing with the Cubs in August 2007.
Rhee retired the first eight batters and did not yield a hit until red-hot Erik Komatsu singled with two outs in the fourth inning. He set down the next eight Manatees before turning things over to the Daytona bullpen.
By not allowing a runner past first base, the Seoul native lowered his ERA from 7.45 to 4.60. While opponents are hitting .237 against him, Rhee has issued only four walks while striking out nine in 15 2/3 innings.
Last season, recovering from Tommy John surgery, Rhee made five appearances, including four starts, between the Rookie-level Arizona League and short-season Northwest League. He combined to go 0-1 with a 9.35 ERA.
Rhee debuted in the Cubs organization in 2008, going 4-1 with a 1.80 ERA in 10 starts for Class A Peoria.