Should the Red Sox be worried about Craig Kimbrel?

HOUSTON -- Craig Kimbrel stood on the mound, his back to home plate, and stared out at the bleachers in right-center field as Houston Astros slugger Colby Rasmus rounded the bases in the ninth inning Sunday night.

Talk about a bad look.

Unfamiliar, too, for the new Red Sox closer. Through his first six big-league seasons, Kimbrel was as lights-out as humanly possible, which is why it took four prospects to pry him away from the San Diego Padres in a November trade. But for a 27-year-old with a 1.63 ERA who had averaged 14.5 strikeouts per nine innings and is under contract through at least 2017, it seemed like a risk worth taking.

In the end, given Kimbrel's age and track record, it probably still will be.

But that doesn't change the fact that his first month with the Red Sox has been ugly. Kimbrel allowed a game-winning three-run home run to Baltimore's Chris Davis in the Fenway Park opener on April 11, walked Toronto's Troy Tulowitzki to force in the go-ahead run in the eighth inning of a Patriots' Day loss last Monday, and now this, a game-tying two-run shot by Rasmus in an eventual 12-inning, 7-5 Sox victory.

Worried yet?

"We've got full trust in Craig," manager John Farrell said.

Fair enough. Kimbrel certainly has earned the benefit of the doubt. But what if he already has reached his peak? Is it even possible that his most dominant days might be in the past?

Consider this: From 2010-14, Kimbrel allowed an average of 5.0 hits and 0.4 homers per nine innings with an adjusted ERA of 266 for the Atlanta Braves. Last year, with the Padres, he gave up 6.1 hits and 0.9 homers per nine innings with an adjusted ERA of 144, still well above the average mark of 100 but an ever-so-slight dip from his ridiculously high standard.

But it's also worth noting that Kimbrel's strikeout total last season (13.2 per nine innings) was on par with his numbers from 2013-14 (13.5), and his 97.3 mph average fastball velocity was consistent with his career norm.

"The times I did see him last year he looked like I remembered," Red Sox senior vice president and former Braves general manager Frank Wren said after Kimbrel was acquired. "Velocity-wise and his stuff, he has been dominant since he arrived in the big leagues. You base it on your scouting reports and the analysis that our guys have done, and they feel very comfortable with the quality of his stuff that he continues to exhibit. Our scouts that saw him late in the year saw his stuff really as good as ever."

Indeed, velocity hasn't been Kimbrel's problem thus far, his fastball remaining in the high-90s. Davis turned around a 97-mph heater, while Rasmus hit one that was clocked at 98. Instead it has been the location. Davis and Rasmus are low-ball hitters who got pitches that were down and too far over the plate. Kimbrel also has walked nine batters and thrown only 59 percent of his pitches for strikes.

Farrell conceded that Kimbrel's curveball has lacked definition -- "There have been times where it's gotten a little sweepy," he said -- but for the most part, hitters are beating Kimbrel because he isn't putting his fastball in the right spot. He isn't about to stray from the hard stuff, though, and he wouldn't second-guess his pitch selection to Rasmus.

"No, that was the pitch I should've thrown. It was just a bad location," Kimbrel said. "Any time you leave it over the plate, it's got a chance to get hit. It wasn't where I was trying to throw it. If I get a chance to face him again, the sequence is going to be the same, but hopefully the execution of the pitches is a little better.

"Both of the home runs I've given up this year have been pitches down in the zone to power hitters. I get those pitches up in the zone and we might be talking about a different situation, but that wasn't the case."

So, how does Kimbrel fix it? He has had rough stretches before. Last season, in particular, he allowed 10 runs on 12 hits and four walks in 9-2/3 innings over a stretch of 11 appearances from April 18 through May 19. For the most part, though, he hasn't dealt with much adversity in a dominant big-league career.

"Every player goes through a stretch where you're not very happy about your performance," Kimbrel said. "We're talking about two pitches or three pitches that I've made mistakes on that have kind of hurt me so far this year. How do I go out there and get rid of those situations? Just executing. You never want to go out there and fail. I've had some pretty rough outings so far at the start of this year. I've had some really good outings as well. Just kind of trying to find the middle line and going out there and being successful.

"We're still in April right now. By the end of the year, we're going to be looking back at this and talking a little differently."

Chances are, Kimbrel is right.

But that doesn't mean the Red Sox need not worry in the meantime.