​Using the Yahoo Player Rater, I found several hitters that were drafted in the later rounds or went undrafted that were ranked highly based on their fantasy productions. These hitters have been unexpected fantasy contributors, which many fantasy managers have been enjoying throughout the season.Can we trust that these hitters will continue succeeding in the second half? Have they shown any new skills or underlying metrics that have contributed to their success? Or are there parts of their fantasy profiles that could be fool’s gold, meaning we should be cautious moving forward? We’ll examine these hitters to answer these questions for the second half.AdvertisementAdvertisementAdvertisementWalker has been one of the most profitable hitters on any player rater, especially since he was undrafted in many formats. He has already set career bests in several categories. Walker’s .346 BABIP is fueling the higher batting average (.294), though he can run higher BABIPs. The tools have been loud for Walker.Here’s a look at Jordan Walker’s bat speed distribution over the past four seasons.(Corbin Young)Walker maintains a lower contact rate (71.6%) with elite bat speed (79.2 mph). He is using a more closed off stance with his feet closer together (21.9 inches). That’s helping Walker hit more balls in the ideal attack angle (5 to 20 degrees) 54.4% of the time, three points above his career average. I’ve theorized that those stance changes help Walker have a better approach against different pitch types.Here’s a look at Jordan Walker’s expected wOBA over the past four seasons.(Corbin Young)That’s been evident in Walker’s wOBA improving against all pitch types. Walker’s .391 wOBA against fastballs increased by 100 points with an 85 point jump against breaking pitches (.334 wOBA). His .448 wOBA has been over two times higher than the .168 wOBA against offspeed pitches.AdvertisementAdvertisementAdvertisementThat data aligns with Walker barreling the ball more often, with a 9.4% barrel rate per plate appearance while pulling the ball into the air 16.8% of the time. For context, he had a 6.8% barrel rate per plate appearance and a 13.7% pulled air rate throughout his career.Walker is built like a linebacker with elite speed and athleticism. Listed at 6-foot-6 and 250 pounds, Walker boasts a 92nd percentile Sprint Speed. He has been running more often this year, with an 18% stolen base opportunity rate, up from 13% throughout his career. There’s the potential for 20+ stolen bases within Walker’s profile.Walker has shown significant swing changes with more hard-hit balls into the air, leading to more barrels. He is finally unlocking his power ceiling. Walker has the tools and skills to trust into the second half.AdvertisementAdvertisementAdvertisementI discussed Lopez in an offseason article as a hitter that could be one step away from being even better. Lopez has been fortunate with a .370 BABIP supporting a career-high batting average at .334 when we toss out the 10