BOSTON -- More than three months had passed since the Boston Red Sox last played the Kansas City Royals. Still, Boston manager John Farrell had his answer cued up Friday when asked his opinion on why the defending World Series champions were able to roll into Fenway Park with 15 wins in their past 18 games.

"The bullpen," Farrell said. "They haven't given up a run since who knows how long. It's been nearly 40 innings."

Indeed, when Royals reliever Peter Moylan was charged with a harmless run in the ninth inning of a series-opening 6-3 victory, it ended the Kansas City bullpen's run of 41⅓ consecutive scoreless innings, the majors' longest streak since the Kansas City Athletics' relievers went 44 innings without giving up a run in 1966.

There are other reasons for the Royals' surge, of course, just as the Red Sox's loss on Friday night could be pinned on multiple issues, including five first-inning runs allowed by starter Steven Wright and 12 men left on base after a 4 for 15 spell with runners in scoring position, the latest in a recent stretch of games in which Boston hasn't cashed in scoring opportunities.

"I'm confident that this will turn," Farrell said.

And considering the Red Sox still lead the majors in runs scored, he's probably right.

But Farrell doesn't feel as confident in his bullpen. He doesn't trust Brad Ziegler against left-handed hitters, even though the right-handed submariner was a closer in Arizona before being acquired in a July 9 trade, and has no faith at all in struggling Junichi Tazawa or lefty Fernando Abad, who came over from the Minnesota Twins at the trade deadline. Koji Uehara's strained right pectoral muscle is healing, but even if the 41-year-old setup man returns in September, there's no telling whether he will be effective.

On Aug. 18, Tazawa and Ziegler blew a lead in a loss to the Detroit Tigers. Earlier this week, Farrell stuck with starters Rick Porcello and Drew Pomeranz to give up the go-ahead runs because he trusted them more than his bullpen.

And so, Farrell declared Friday that longtime starter Clay Buchholz will get opportunities to safeguard leads in the eighth inning now that he is moving back to the bullpen after three successful spot starts. As second chances go, this one is somewhat stunning, especially since Farrell said as recently as July that he was hesitant to use Buchholz in anything other than lopsided games. If the Red Sox weren't concerned about starting depth, Buchholz might have already been released.

"I don't want to outline a defined role [for Buchholz], but at the same time, it's going to be responsibility to it," Farrell said. "He's going to be in an important role for us in the bullpen."

At this point, exactly when Farrell might turn to Buchholz is anybody's guess. Other than closer Craig Kimbrel, there isn't a pitcher in the Red Sox's bullpen with an established role, which is problematic for relievers who typically thrive when they know the situations in which they will be called upon.

"Just talking to [Abad], coming from Minnesota, shoot, he had a defined role as the eighth-inning guy, so he's like, 'Man, I'm throwing every two to three days and it's 94 to 96 [mph]," Buchholz said. "He's like, 'My first few days here, I'm up and throwing [more often] and it's 91 to 92.' It takes a little bit of time for those guys to figure out how they're going to be used, what their role is. It takes repetition to figure that out and know when you're going to be called upon and what situation it's going to be."

The bullpen chaos is partly a function of bad luck. When the season began, the Red Sox planned on Uehara, Tazawa and Carson Smith as the setup crew for Kimbrel. But Smith underwent season-ending Tommy John elbow surgery in May, Uehara has been out since early July and Tazawa looks gassed after having been leaned on heavily over the past few years.

But it's also an indictment of the Red Sox's depth. Right-handers Matt Barnes and Heath Hembree have had their moments, but ultimately the Red Sox needed to trade for Ziegler and Abad because their internal replacements for Smith and Uehara weren't reliable enough.

Contrast that with the Royals, who lost closer Wade Davis (flexor strain) and right-hander Luke Hochevar (symptoms of thoracic outlet syndrome) last month. Setup man Kelvin Herrera took over in the ninth inning, erstwhile closer Joakim Soria moved into the eighth and lefty Matt Strahm has posted a 0.84 ERA and a 19-to-3 strikeout-to-walk ratio in nine appearances since getting called up from Double-A.

But while Kansas City manager Ned Yost has simply turned to the next man up in the Royals' bullpen, Farrell is desperate for merely a few good men.

So, Buchholz will get a chance. And when rosters expand next week, it's likely hard-throwing right-hander Joe Kelly will too. Exiled to Triple-A and banished to the bullpen, Kelly has allowed one run, struck out 23 batters and walked only one in his past 14 innings.

"He will help us, yes," Farrell said. "He's getting more swing-and-miss to his fastball, in large part because I think he's doing a good job of elevating it in key spots. He's going to have an opportunity to contribute and help this club.

"We're still trying to mix and match and match up in the eighth inning. Depending on the given day, or if we're in a stretch of right-handed hitters, yeah, that's likely to be Brad in that spot."

Beyond that, it's anybody's guess. And if the relief roles don't get sorted out soon, it could mean the difference between holding on to a playoff spot and the Red Sox watching the bullpen-sturdy Royals pass them by.