The Red Sox on Tuesday announced that they'd optioned left-hander Eduardo Rodriguez back to the minors. To replace him on the active roster, the team recalled reliever Pat Light.

The moves comes after Rodriguez on Monday allowed nine runs in 2 2/3 innings against the Rays. For the season, his ERA now stands at 8.59 after six starts. As for what's ailing Rodriguez, who was quite effective as a 22-year-old rookie in 2015, there's this ...

At the very least, the Red Sox believe it's nothing physical.

Rodriguez's struggles, though, are the rotation's struggles writ small. This season, Boston ranks 11th in the AL in rotation ERA and 10th in FIP (Fielding Independent Pitching), which is scaled to look like ERA but reflects just those outcomes that have nothing to do with fielding -- i.e., strikeouts, walks, and home runs allowed. As such, it's a better measure of raw pitching skill than ERA is. Things have been even worse of late, as the Sox's rotation in June has put up an ERA of 5.39 and a FIP of 5.43. Bear in mind that the Sox over the winter added David Price at great cost. Price has now pitched to a 4.68 ERA this season.

Boston indeed has a tremendous offense this season, but the rotation needs to at least be adequate in order for the Sox to remain in contention in the highly competitive American League. Steven Wright has more than done his job, but the struggling remainder hasn't.