SEATTLE — Craig Counsell had seen enough. The Chicago Cubs manager did not wait around to see if Shota Imanaga would let the Seattle Mariners back into Sunday’s game. With a three-run lead, two runners on and no outs in the third inning, Counsell walked out to the mound at T-Mobile Park to take the ball, ending the shortest outing of the Japanese pitcher’s major-league career.The move underlined a message Counsell had already delivered: “It’s go time.”Imanaga has been the club’s most consistent starter this season, accounting for 145 1/3 innings and a 3.78 ERA while spending zero days on the injured list. But the lefty didn’t have it this time, throwing three first-pitch strikes to 14 batters and needing 72 pitches to get six outs. He wasn’t sharp enough or economical enough to go much further.Who should win NL MVP?Joe CrisalliThe moment illustrated a sense of urgency as well as the options Counsell has at his disposal. As Ian Happ’s grand slam off Mariners right-hander Bryce Miller ricocheted off the right-field foul pole in the top of the third inning, Chicago’s manager continued to think ahead.Counsell quickly signaled for Aaron Civale, who was acquired in July after the Athletics designated him for assignment. Civale worked out of the jam Imanaga created and submitted four scoreless innings before Chicago’s offense exploded in a 19-2 victory that avoided a panic-inducing sweep.“This is why we have some length in the bullpen,” Counsell said. “As soon as Ian hit the home run, honestly, my thought was, ‘If Shota’s in trouble, we’re going to go.’”The Cubs still have 31 games over the final 35 days of their up-and-down season, just enough time for a long-shot attempt to overtake the Milwaukee Brewers, and too many variables to rule out the possibility of an epic collapse that preempts playoff baseball in Wrigleyville.Given the drama and extremes thus far — two 10-game winning streaks, a 10-game losing streak, Pete Crow-Armstrong’s dazzling MVP campaign, an avalanche of pitching injuries, a buying spree at the trade deadline, 21 blown saves, 40 comeback victories — these next chapters will not be boring.Sunday’s game got so out of hand that Pedro Ramírez hit a grand slam off Mariners backup catcher Jhonny Pereda in the eighth inning, and it only went down as a footnote. Counsell then switched Cubs catcher Carson Kelly to pitcher in the ninth inning to record the final three outs and give his bullpen a break.With his proven track record and direct method of communicating, Counsell gets buy-in from his players who might not always agree with his decisions.“We have a group that understands the bigger aspirations,” Happ said. “There’s a pretty common focus on whatever it takes to win baseball games. And that’s about it.”Happ, the club’s longest-tenured player and a free agent after this season, knew the trade-deadline addition of Tyrone Taylor would subtract some of his at-bats in certain matchups. Jacob Webb is still Chicago’s closer, and Daniel Palencia understood he wouldn’t get his old job back when the Cubs activated him off the injured list. Pitchers such as Civale, Colin Rea, David Peterson (back in the rotation) and Javier Assad (optioned again to Triple-A Iowa) have accepted their roles as swingmen.“It’s just a lot of trust with what each of us do,” Civale said. “There’s a lot of confidence that’s being instilled. The situations of when guys are being used, how they’re being used, it all plays really well.”It has to because the Cubs built a quality rotation — each member of their current starting five has been an All-Star at some point — that does not feature a traditional No. 1 starter.It will be a priority to get Imanaga back on track and avoid the late-season slump that led Counsell to go with a bullpen game last October rather than use Imanaga on the night the Brewers eliminated the Cubs from the playoffs.“It was just a bad day,” Counsell said, pointing out how well Imanaga pitched in his previous outing against the Chicago White Sox. “You could just tell the misses were far bigger than normal. The velocity was down a little bit from the beginning. We’ll just have to regroup.“This was kind of isolated right now, and obviously, he gets to prove it the next time out.”Like teammates who have been reassigned and taken on lesser roles, Imanaga understood the manager’s reasoning.“The feel wasn’t as good as usual,” Imanaga said through an interpreter. “Those adjustments that I needed to make didn’t come quick enough. I couldn’t show that it was getting better.”Again, this is “go time.” The previous weekend, the Cubs had cut their deficit in the National League Central to three games. Joshua Báez, a boom-or-bust prospect for the St. Louis Cardinals, then hit three home runs in the first three at-bats of his major-league debut to beat the Cubs at Wrigley Field.The Cubs (75-56) split four walk-off games over six days, beating the White Sox twice and losing their series against the Mariners. Those coin flips left Chicago seven games behind the Brewers heading into Sunday’s matinee. At the same time, the Philadelphia Phillies (73-58) and San Diego Padres (71-60) have picked it up recently, gaining ground in the wild-card standings.The Arizona Diamondbacks (69-62), the first team outside the NL’s playoff picture, have Merrill Kelly, Brandon Pfaadt and Eduardo Rodriguez lined up for a three-game series that begins Monday at Chase Field, where the Cubs historically have not played well.“Look, we have to win baseball games,” Counsell said. “Do you know what the other teams around you are doing? Of course you do. But we have to win games. And when you don’t really control what the other teams do, it’s about your team and you winning games. That’s really all you can do. I’m not sure what me looking at and worrying about that stuff will do for the Cubs.”