Starlin Castro is only 25 years old and has big things ahead of him. Having already played in five full seasons, Castro is already on pace to reach 1000 hits soon, possibly before he even turns 26 which would be a feat.
So far thus season he is batting .271 which isn't on par with what he normally can do, but if he can get a few extra at bats, Castro could very easily get 180 hits for the season. Castro has a decent amount of power for a shortstop, having hit at least 10 home runs in each of his last 4 seasons with a career high 14 last season. He's only hit 3 so far this season which means that he could finish off with perhaps 10 to 12 if he plays enough.
Castro seems to be slacking a bit this season when it comes to doubles as he's only hit 4, meaning he's on pace to hit anywhere from 12 to 15 doubles. That's decent, especially for a shortstop, but not when he hasn't hit fewer than 29 doubles in any of his 5 seasons. Castro also has not had a triple yet this year, he hit 3 in all of 2013 and 2014 combined and more than 20 in 2011 and 2012.
He hasn't been doing too well in stealing bases either but seems to be getting back on track this season. In 2011 and 2012, Castro stole at least 20 bases in each year while he only combined for 13 in 13 and 14, though he's already had 4 steals in 2015 putting him on track for around 13. When it comes to producing runs, Castro is at the top of his game and already has 24 RBI's so far, which would put him at just over 90 for the year, well above his career best of 78, and in terms of Runs, Castro is on pace for to score roughly 60 times.