This was in a Pro baseball game I was working at this weekend(not as a umpire). R1 no outs. Batter hits a long fly ball to left. OF made an amazing catch. Runner was about to round second when catch was made and did a U turn and touched the base on his way back. Had he rounded the base and headed towards third I know he would have had to retouch 2nd on the return. Since he didn't actually head towards third except as part of his arc on the Uturn I assumed it was OK. No one appealed it so I assumed he did the right thing but wasn't sure if it was correct. I wondered if he should have still had to retouch 2nd.