Castillo threw six scoreless innings against the Giants on Friday night to get his fourth win of the season. He struck out 11 while allowing two hits and five walks. He generated 15 swings and misses on his changeup, accounting for nine of his strikeouts, and threw his changeup 40 times in the effort, Mark Sheldon of MLB.com reports.
It's those five walks that drove Castillo's pitch count over 100 after six innings, leading to the early exit. He was facing a Giants team that scored four against him in his previous outing, his worst so far this season, albeit without Buster Posey, who is now on the injured list. He next faces a red-hot Cubs lineup back in Great American Ballpark, a challenge that will really test his newfound ace level.