Carlos Contreras is a right-handed reliever of the Cincinnati Reds A+. He was signed out of the Dominican Republic in 2010 and was just picked in 7th round of Dominican Winter League draft. His fastball gets up to 96 MPH with a slider (at 86 MPH) he can't really control. His control is an issue, which is why his FIP is 4.42 and SIERA is 3.81 in his career (not counting complex league stats). He has shown the ability to miss bats, but has had some problems with walks.
Robert Stephenson is considered by many to be the Reds best pitching prospect. The right-handed starting pitcher was drafted in the late 1st round in 2011. He sits (at least he did in his last start, where I watched him) in the 95-96 MPH range with a decent breaking ball. So far this year, between the Pioneer League and Midwest League, he has a 3.09 FIP and 2.84 SIERA. He can throw his curveball for strikes and locate the fastball low and high. His command is pretty good for that level, especially once you consider he is just 19. It seemed his problems control wise was against lefties when he would try to work outside and low and just miss. He got both whiffs and quite a bit of weak fly-balls (although he did give up a homer to a right-hander that isn't really a power hitter on an inside fastball). You would like to see him throw his curveball more in games, unless the Reds are specifically telling him to throw mainly fastballs (which I have heard some organizations do with their younger pitchers). So far in the Midwest League, he is getting less ground-balls than league average, which may be because he is throwing so many fastballs. It is hard to project a 19 year old that is nowhere near a finished product, but he certainly has the stuff to not only succeed at the big league level but to be dominant at times. You would like to see a third pitch to get hitters out the third time around, which he isn't having to do right now (thanks to pitch counts). However, his control is pretty good and he is pitching really well against hitters that are older than him.