Each year, there are 15 to 20 MLB players who seemingly come out of nowhere and bring up their names to the attention of fans and league higher ups. However, through advanced stats, some of these players could be seen, even before the season starts.
Starting fresh at catcher, Willians Astudillo of the Twins put up very good numbers in limited at bats in 2018. In 93 plate appearances, Astudillo struck out only three times, good for a strikeout percentage of 3.1, lowest in the league among players with at least 50 at bats. Astudillo also makes exceptional contact, putting the ball in play all but five times last season when he was at the plate. Moving to first base, Daniel Vogelbach, Mariners, puts out huge power numbers that stick out. His launch angle in 2018 was 10.1, comparable to superstars such as Giancarlo Stanton and Aaron Judge, his average exit velocity is 90 miles per hour, meaning most of the balls he hits are hit very hard.
Athletics second baseman Franklin Barreto, long considered a top prospect, could also be poised for a breakout season. The last two seasons, he has increased his OPS and OPS+ from below league average, and now to league average. He is maturing and yet to hit his prime.
At shortstop, Adalberto Mondesi, who had a nice second half of 2018, could have a huge year. His power numbers came on, and he had a wRC+ of 114, meaning he was 14 percent higher than league average, this coming after only playing in 75 games.
Finally, rounding out the infield, third basemen, Johan Camargo, of the Braves. Camargo had a OPS+ of 116, which is 16 percent higher of the league average, and with increasing power numbers, he could join a Braves team with a lengthy list of superstars.
Now in the outfield, White Sox left fielder Daniel Palka could rise to fame this season. In his rookie year, he had an OPS of .778 and an OPS+ of 111, and really came into his own as far as his power numbers. He put up a largely overlooked rookie season at age 27.
Victor Robles, the Nationals center fielder, is another candidate. Robles, who has always been a highly regarded prospect, will now have the opportunity to play with the departure of Bryce Harper. In limited time last season, he slugged three home runs, which is a lot for Robles in that amount of time, and had an OPS+ of 127, meaning that the was on pace to be 27 percent above the average major leaguer, an astonishing number for a young player.
Finally, in right field, Franmil Reyes, of the Padres, is poised for a big season. Reyes, who stands at six foot five and weighs 275 pounds, put up impressive hitting numbers in 2018, slugging out 16 home runs and batting .280 in a limited number of at bats. He had an OPS of .838, which was comparable to that of what NL MVP Christian Yelich put up in the first half of the season. If Reyes can get enough consistent playing time, he could become a true superstar.
For pitchers, the Cardinals own Jack Flaherty is going to have a big year, and the stats definitely back that up. Flaherty’s strikeout numbers in 2018 were insane. He struck out 182 hitters, which is standard for most pitchers that pitch 200 innings. However, Flaherty only pitched 151. That puts his strikeouts per nine, meaning the average numbers of strikeouts he would get per game, and 10.8, which is extremely high. His hard hit percentage is also very low, being just above 30 percent. Finally, the best thing going for Flaherty is that he did all this at 23, meaning he has plenty of room to grow into even more of a superstar pitcher. The reliever to watch in 2019 is Giants set up man Reyes Moronta. Moronta had a better year that expected in 2018 and was overlooked with the west coast factor, playing all of his games when most of the country was asleep. Moronta, like Flaherty, have huge strikeout numbers, a 10.9 strikeout per nine to be exact. He also had the ninth lowest slugging percentage allowed, a .235. He is also developing a third pitch, a changeup, to go with his stellar fastball, which averaged 97 miles per hour on in 2018, and his slider.
These stats used and more can all be found at baseballsavant.com.