On April 15, when the Cleveland Indians' rotation was lugging around a major-league-high 6.79 ERA and Tribe fans were begging for Mike Clevinger to be summoned from Triple-A Columbus, pitching coach Mickey Callaway kept preaching the same message: He told his starters to keep doing what they were doing, even if the results appeared to be crying out for a Plan B.

The pitchers said they felt good, and their stuff matched their upbeat self-evaluations, so Callaway kept assuring them that the numbers would get better -- and soon.

"We normally don't look at how many runs we give up,'' Callaway said. "We ask ourselves, are we getting ahead in the count? Are we walking guys? Is our stuff there? Are the strikeouts there? ... All those peripheral numbers were good. We were just giving up runs.

"A lot of times guys can misconstrue a bad game for, 'I need to do something different,' when you know what? You just gave up some runs that night. It happens. When you start changing, you can't be consistent and you really start to struggle. The guys did a good job of sticking with what they know and making sure they focused on the little things. And here we are.''

One encouraging spin through the rotation doesn't guarantee a smooth ride for the 144 games left on the schedule. But as the Indians welcome the Houston Astros for a clash of division leaders Tuesday, Callaway's faith in the starting rotation -- and the underlying metrics -- appears to be well-founded.

Since their early rough patch, Cleveland's starters look more like the group that helped lead the team to 94 wins and a World Series appearance in 2016. During a five-game winning streak that ended with a 6-2 loss to the Chicago White Sox on Sunday, Corey Kluber, Carlos Carrasco, Danny Salazar, Josh Tomlin and Trevor Bauer logged a combined 1.53 ERA -- with six earned runs allowed in 35.1 innings.

Like Callaway, the front office trusted that the malaise would soon pass. Even as Cleveland's starters bottomed out with that 6.79 ERA, they sported a major-league-high .351 batting average on balls in play, which suggested a lot of balls were finding holes. They also ranked second among MLB rotations with a 3.05 xFIP, which estimates expected run production based on numbers independent of a pitcher's defense, an indication that they should have been faring better than the high run totals suggested.

"We weren't reading into the numbers with too much concern, because these guys were all feeling so good and there was no degradation in their stuff or their command,'' said general manager Mike Chernoff. "When you dug a little deeper, you saw they all looked like the same guys they were last year.''

Teams coming off deep postseason runs inevitably encounter questions about the dreaded "hangover'' effect, but the Indians did not enter the 2017 season with a one-size-fits-all list of potential concerns. Carrasco and Salazar missed all or most of the postseason with injuries, so their biggest issue was health rather than mileage.

Conversely, the Indians rode Kluber to the limit in October. He made three starts on short rest and threw a career-high 249 1/3 innings between the regular season and the postseason, so the staff wanted to make sure to strike the right balance between preparation and recovery for him heading into 2017.

During the offseason, Callaway arranged a conference call with Tim Belcher, Jason Bere, Scott Atchison, Steve Karsay and Bruce Chen -- all former big league pitchers with the organization -- and solicited ideas that might help Kluber. The group discussed everything from Kluber's long-toss regimen and bullpen sessions to his projected spring training workload.

Callaway relayed the suggestions to Kluber, who told him the only thing that really mattered was being ready by Opening Day. Once that was resolved, the Indians knew Kluber would tend to the particulars.

"There's a lot in this game you can control and a lot you can't control,'' Chernoff said. "Corey takes care of everything you can control. This guy is thinking of preparation and recovery from the second he gets off the mound up until he's back on the mound five days later.''

Cleveland's starters still have some potential trouble spots to navigate. Tomlin hasn't generated many swings and misses with his 87.2 mph average fastball. Kluber has allowed five home runs in 27 1/3 innings. Bauer has looked good the first time or two through the batting order, but he has a 12.91 ERA in the fourth through sixth innings. And Salazar has run up some big early pitch counts while striking out a whopping 36 batters in 22 2/3 innings.

After a heavy workload in the 2016 postseason, the Indians are relying on Corey Kluber to show no signs of slowing down this season. Ron Vesely/MLB Photos via Getty Images

But they can take comfort in knowing the bullpen is still adept at protecting leads and cleaning up any messes they create. Andrew Miller and Cody Allen have combined to allow one run in 15 innings, and they've looked every bit as dominant as they did during the postseason. Miller even emerged unscathed from his stint in the World Baseball Classic -- an excursion that kept manager Terry Francona on edge throughout spring training.

"It just goes back to how prepared these guys are,'' Callaway said. "You see Andrew Miller at the start of a series, and he's buried in video and preparing for hitters that he probably could do really well against if he didn't prepare. That takes him to a new level of effectiveness. And Cody Allen does the same thing.''

During the Indians' current 6-2 run, the everyday lineup has taken strides toward greater stability. Jason Kipnis is back from a shoulder injury. Michael Brantley, who appeared in a mere 11 games last season because of shoulder problems, just played in four straight games for the first time this season. Edwin Encarnacion is getting warm, and Francisco Lindor and Jose Ramirez give the Tribe the most dynamic left side of the infield in the game.

But everything begins with the starting pitching. That's been the mandate since Callaway took over as Indians pitching coach in 2013.

"At one of our first meetings, I told our guys, 'When people talk about the Indians, I want them to talk about pitching,'" Callaway said. "The goal is to be prepared in every way -- physically and mentally -- and go out there and attack hitters. I kind of feel like our pitching staff -- especially our starters -- is the heartbeat of the team. If they're going good, we have a really good chance to succeed.''

The Indians refrained from panicking when the early numbers bordered on gruesome. Now that the rotation has restored a semblance of order, it's time for the rest of the AL Central to start worrying.