Statistically, Rhiner Cruz has been one of the worst pitchers in the Majors this year. Selected by the Astros in the Rule 5 draft, Cruz threw 59.1 innings in AA with the Mets last year and was not very unimpressive at all in relief with a 4.58 FIP. This year, he has a 143 FIP - and 4.89 SIERA. He is walking 13.2 % of the batters he faces (exactly the same as David Wright's walk rate this year) and striking out less than 16% of them.
On Tuesday, he nearly drilled Andrew McCutchen in the head. He has hit 2 batters this year (3 if you count his rehab assignment in AAA), but there have been several times this year where he has been a serious safety hazard, drawing dirty looks from opposing teams.
Something I've noticed is that the Astros have been fiddling with his release point all year. He is coming in more sidearmed than he was earlier in the year. These release point charts kind of help point that out:
Either way, he is interesting because he is averaging 95.47 MPH on his fastball (the good kind of interesting, as one could say his extreme wildness and potential to seriously injure people is interesting in a sadistic sort of way). Already at 25, it would take a really drastic change for him to harness the fastball, but you can see why the Astros took a chance on him in the Rule 5 draft.