Joe Kelly, the "number 5" starter currently leads the starting rotation with an ERA just above 4. He was doing quite well until the 6th inning of his last start. I don't believe that his performance was as bad as his stat line. Craig Breslow immediately gave up a hit to hang two more runs on Kelly, but when Kelly handed over a bases loaded, no outs situation most of the blame still lies with Kelly.
The next lowest ERA starter is "Ace" Clay Buchholz at 4.84. Buchholz has been a complete wild card. He could throw a no-hitter or he could have a compete meltdown in the first inning. Nothing would surprise me. His opening day start was a gem against the Phillies, then he melted down for 9 earned runs against the Yankees, he gave up 11 hits but just 2 runs in 6 innings against the Orioles and last night against the Rays he threw 6 innings for just 2 hits, 1 run and 3 walks; but he was already up to 104 pitches at that point.
Next up is "number 3" starter Justin Masterson checking in with a hefty 5.74 ERA. Masterson is 2-0, but he's been the beneficiary of 21 runs of support in 3 starts. Masterson has been as inconsistent as Buchholz, but with a bit more bad than good so far. A borderline quality start against the Phillies, a 7 run 5th inning meltdown that the bats bailed him out of and a good start against the Orioles; but he only managed to go 5 innings.
Wade Miley, the "number 4" starter is currently sitting with a 6.08 ERA. Ironically, Miley was portrayed as an "innings eater", but currently has the fewest innings pitched on the starting rotation with 13.1 in 3 starts. Two "meh" starts where he did fine but couldn't finish the 6th and a 3rd inning 7 run meltdown.
At the bottom of the team ERA is the recently extended Rick Porcello with a 6.63 ERA. Fun fact: Porcello is the only Red Sox starter to have a start go 8 innings. Two quality starts and a meltdown, pretty much par for the course for the Sox starters so far.
This rotation is bad. When they put this staff together I was expecting mediocrity, but they've been worse than that. It's not a big sample size, but every pitcher on this staff has already had a meltdown bad enough to single-handedly lose the game.
The bats are also hard to figure out. They walk a lot. They score a lot of unearned runs. They don't actually get that many hits. The team as a whole is batting .230. The only player above .300 is Xander Bogaerts. Bogaerts is currently in a 1 for 15 slump. Brock Holt is hitting .414, but is not getting regular playing time. With this pitching staff the bats have to step up to compensate.
The bullpen has been solid. They've struggled with inherited runners, but otherwise the results haven't been bad. Tazawa, Breslow and Uehara have yet to be charged with an earned run. Breslow has let some inherited runners score and puts a bunch of guys on, but he's still working his way out of most jams. Uehara needs more work, but has looked good to start the season. Tazawa has been great.
Given all this, it's amazing that the Red Sox are still doing reasonably well at 9-7. They've slid into a 3-way tie for the AL East with the Yankees and Blue Jays. It's going to be an interesting season.