Shota Imanaga impoldes in Cubs' 12-5 loss to White Sox

Cubs left-hander Shota Imanaga turned to look over his left shoulder at the video board showing the replay of the home run he just had given up in the fourth inning Friday.

In a game the Cubs would go on to lose 12-5 to the White Sox, it was the third homer Imanaga had yielded, all on fastballs that caught too much of the strike zone.

This one to Austin Slater was on the outer third of the plate, a little above belt-high, right where he could drive the ball. And the pitch clocked in at just 88.9 mph, well below Imanaga’s season average.

‘‘I just didn’t have consistency tonight,’’ Imanaga said through an interpreter after the game. ‘‘How my body felt versus how the ball was coming out didn’t match up.’’

Imanaga’s start ended after the next batter. He handed the ball over with no outs and a runner on second in the fourth. It was tied for the shortest outing of his major-league career. A team that has won only 38 games tagged Imanaga for seven runs and 12 hits.

‘‘The velo was down, not great location,’’ manager Craig Counsell said. ‘‘It just shows the fine line of pitching in the big leagues of what success and struggles look like. It’s hard to believe that’s the pitcher you saw the last two times make a start. That’s how it works.’’

It was a sloppy game for the Cubs overall, but it was a stunning unraveling from Imanaga, who has been one of their best starters for the last two seasons. His first pitch of the game was nowhere near the plate. His second was over the heart of it, and Sox leadoff hitter Chase Meidroth sent it over the left-field wall.

Imanaga then yielded singles to four of the next five hitters he faced, with Lenyn Sosa’s line drive to the warning track scoring two runs.

The second inning was almost a carbon copy of the first: a leadoff home run, this time from Colson Montgomery, and a string of singles.

Imanaga pitched a scoreless third, which would have been a 1-2-3 inning if a miscommunication between center fielder Pete Crow-Armstrong and left fielder Ian Happ hadn’t allowed a fly ball to drop between them.

By the time Imanaga gave up a homer and a double in the fourth, his pitch count already had climbed to 85. At that point, Counsell called in Chris Flexen, who pitched for the Sox last season, from the bullpen.

‘‘The pitches didn’t feel great coming out of my hand,’’ Imanaga said. ‘‘There were no walks, but I was throwing [pitches] too much in the zone. So I just need to work on that and know that for the next time, even if I do walk a guy, that’s fine. Let’s keep the runs low.’’

Imanaga’s velocity has fluctuated since he returned from a stint on the 15-day injured list with a strained left hamstring at the beginning of the month. But his average fastball velocity had climbed back up to 90.8 mph in his last start, when he held the Red Sox scoreless through seven innings.

On Friday, however, it took another dive, down to 89.1. But he and Counsell said they weren’t concerned about an injury.

Imanaga’s struggles were uncharacteristic of his season, but they also emphasized the Cubs’ lack of pitching depth. Especially while right-hander Jameson Taillon still is working his way back from a calf injury, the Cubs need every start from the top of their rotation to be strong to make up for the uncertainty at the back end.

The Cubs still have their Sunday starter listed as TBD, but right-hander Ben Brown is expected to give them length, whether that begins in the first inning or after an opener.

The Cubs are pursuing pitching leading up to the trade deadline Thursday, but outside help likely isn’t coming until next week.

The position-player market picked up in the last couple of days, with the Mariners acquiring first baseman Josh Naylor from the Diamondbacks on Thursday and the Yankees trading for Rockies third baseman Ryan McMahon on Friday, but the pitching market had yet to get moving.