The Rays prospect collected four more hits, including a pair of doubles, and drove in two runs Saturday in Rookie-level Princeton's 9-5 loss to the Greeneville Astros.
Vettleson extended his hitting streak to nine games with a leadoff single in the fourth inning. His two-run double in the fifth gave him a third straight multi-hit game, and he promptly stole his 13th base of the season.
"I've been really trying to relax every time I go into the box," Vettleson said. "Early on in the season, I was trying to get up for each pitch and just told myself to relax and go straight to the ball and don't put anything extra on the ball. Just going down on the ball from my hands instead of going up with your body."
Vettleson was selected 42nd overall in the 2010 Draft. After signing late, he made his pro debut last month in the Appalachian League and struggled initially, batting .244 with two extra-base hits in the Rays' first nine games. Since July 1, he's hitting .368 with five homers and 25 RBIs to move into eighth place in the league with a .331 average.
"I really like to credit our hitting coach, Wuarnner Rincones," said Vettleson, who's sixth in the league with 45 hits. "He's been really helping me a lot and getting me to relax at the plate. He could tell that I was trying to go for the home runs early on and he put it in my mind to use my hands and that my bat speed would help take care of the rest."
Vettleson, who starred as a pitcher in high school in Bremerton, Wash., also credited a non-baseball source for his surge. It was his father, Jerry, who realized his son was ambidextrous.
"I've been talking to my dad each night. He's been a big help for the mental side of my game each day," the 20-year-old outfielder said.
Vettleson has 16 extra-base hits this month and has drawn 15 walks while striking out 14 times. In June, he walked once and fanned 11 times.
"One thing that our manager, Mike Johns, really stresses upon is getting that fastball," Vettleson said. "When you really take it into focus and say, 'I'm going to hit it,' it makes it easier to let the off-speed pitches go. There's a lot of guys who throw off-speed early, but there's going to be one pitch you can hit, and if you can square it up nothing else matters."
Ryan Brett, selected two rounds behind Vettleson, was 2-for-5 with a homer, two RBIs, two stolen bases and two runs scored for Princeton. Fellow first-rounder Josh Sale doubled and walked twice.
"This is a great team with great players and it's nice having a lot of guys with a lot of talent," Vettleson said. "I have a lot of guys that can take the pressure off me and no one is getting pitched around because we have guys behind them that can hit."
Jose Vargas' grand slam capped a seven-run seventh inning as the Astros erased a three-run deficit.