If we look at Eduardo Rodriguez's overall numbers from 2017 for the Boston Red Sox, he at least took a step in the right direction after struggling to a 4.71 ERA in 107 innings the year before. The southpaw tossed a career-high 137.1 innings while producing a 4.19 ERA with new personal-bests in strikeout rate (25.8%), SIERA (4.05), and fWAR (2.1), but if we split his performance into two halves, it's just as troubling as 2016 was.

Prior to hitting the disabled list in early June with a knee injury, Rodriguez was well on his way to a breakout campaign. Through his first 61 frames, he owned a 3.54 ERA that was supported by a 3.99 SIERA thanks to a strong strikeout rate (26.3%) and a walk rate (8.5%) that was at least slightly improved.

But it was another story in the 76.1 innings that he pitched to finish off his third year in the big leagues. His strikeout rate (25.4%) and walk rate (8.7%) held pretty firm and his 4.10 SIERA also wasn't drastically different, but it resulted in a 4.72 ERA.

The struggles lie in his pitch selection, which looked to have a significant impact on his contact numbers. The below table shows how the usage of his fastball, slider, cutter, and changeup transformed through the year, along with the value of each offering, per FanGraphs.

The only above-average pitch he consistently had throughout the year was his changeup, yet his usage of that pitch when down after a strong first half.

The batted-ball numbers line up here, too -- his line-drive rate (20.9% to 23.0%) and hard-hit rate allowed (28.9% to 32.1%) both got worse, as opposing hitters also made more contact overall (73.6% to 76.2%). When seeing all these numbers, it shouldn't be surprising to see his BABIP go from .267 in the first half to .322 in the second half.

This would be enough to handle heading into 2018, but he'll also be coming off knee surgery, so there are multiple things to watch here as E-Rod works his way back onto the mound next season.