The return Tuesday by the Royals to ground zero was wet but otherwise uneventful. Their 7-1 loss to the Detroit Tigers at Kauffman Stadium was routine in comparison to Monday’s 19-4 annihilation.</p><p> Even so, two problems stood out: Kyle Davies continued the rotation’s recent implosion by lasting just four innings. And José Guillen remains mired in an April-like slump.</p><p> There was lots more — Joel Peralta allowed three runs in a 37-pitch fifth inning — but start with Davies and Guillen because the rotation and Guillen are typically viewed as two of the club’s chief strengths.</p><p> Davies allowed only two runs but required 96 pitches to get 12 outs. His early exit left the rotation with just four quality starts over the last 20 games while compiling a 2-9 record and a 7.13 ERA.</p><p> “I knew I wasn’t locating the ball very well,” he said. “I don’t know how many three-ball counts I had, but it was a lot. A starting pitcher needs to get as many outs as you can. Pitching four innings, especially with our bullpen being depleted, is not good for the team.”</p><p> Manager Trey Hillman was more blunt.</p><p> “You have to pitch, and we know we have to pitch,” he said. “There’s no other way to say it. Especially against the competition we’re playing and the schedule. These guys have it clicking.”</p><p> Guillen went zero for four and stranded three runners, including two in scoring position with less than two outs, on a night when manager Trey Hillman benched slumping Alex Gordon and Mark Teahen against Tigers lefty Kenny Rogers.</p><p> The grim math: Guillen is batting .149 in his last 20 games with just 11 hits in 74 at-bats. He has no homers and only five RBIs in that span. His average has plummeted from a season-high .293 to 265.</p><p> “I don’t think it’s pitch selection,” Hillman said. “He’s just missed on many of his swings. There’s no production since the (All-Star) break. I think he’ll get it going.”</p><p> To be fair, only Mark Grudzielanek seemed able to solve Rogers. That’s no surprise. Grudzielanek had a two singles and a double in four at-bats and is now 15 for 23 in his career against Rogers.</p><p> Guillen entered the game at six for 17 with two homers against Rogers but failed to get the ball out of the infield. It continues Guillen’s roller-coaster year. He batted .165 in his first 30 games, then .380 in his next 44 games before his current slide. </p><p> Throw in a rain delay of 2 hours, 20 minutes in the Royals’ seventh, and it made for a long, miserable night. </p><p> Rogers improved to 8-6 by limiting the Royals to one run and four hits in six innings before the rains hit. He struck out four and walked one before Fernando Rodney and Joel Zumaya closed out the victory.</p><p> “(Rogers) is a good veteran pitcher who knows how to pitch,” shortstop Mike Aviles said. “He pitched his game. He came out with a plan. He pitched both sides of the plate. He basically shut us down.”</p><p> The Tigers improved to 51-49 and matched a season best by moving to two games better than .500.</p><p> Five different players had RBIs in a balanced 12-hit attack. Placido Polanco gave Detroit a 2-1 lead with a two-out homer in the third inning and contributed a double to the three-run fifth.</p><p> The Tigers scored their final two runs in the ninth against Robinson Tejeda after capitalizing on a throwing error by first baseman Ross Gload.</p><p> Tejeda lost track of the outs and began walking off the mound after striking out Carlos Guillen for the second out. It was probably fitting that Magglio Ordoñez followed with an RBI single as payment for the mental lapse.