CHICAGO -- The Rays hadn’t yet arrived at Guaranteed Rate Field on Tuesday when they received the news that Tyler Glasnow would be sidelined for some time by a partially torn UCL and flexor strain. Infielder Mike Brosseau called it “heart-wrenching” and “a tough pill to swallow,” while manager Kevin Cash used the words “gut punch” when asked about losing his ace.

A tough, emotional day for Tampa Bay didn’t get any better once the game got under way, as the Rays mustered little offense against lefty Dallas Keuchel and went down quietly, 3-0, at Guaranteed Rate Field.

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It was only the Rays’ sixth loss in their last 30 games, and the margin of defeat made it even more uncharacteristic. This was only the third time this season they’ve been shut out, and they hadn’t been blanked since Gerrit Cole beat them, 1-0, at Tropicana Field on May 12. They hadn’t lost a game by more than two runs since May 8 in Oakland. Still, 53 of the Rays' last 56 games have ended with them either winning or losing by fewer than three runs.

Statistics like that might make you appreciate two things: how special of a run the Rays have been on for the last month, and how rare nights like Tuesday have been for them this season.

“These days are going to happen. No one is down or feeling sorry about themselves in that clubhouse,” center fielder Kevin Kiermaier said. “But it's a slight reminder that we've got to go out there and perform and execute day in, day out to get wins, and we just weren't the better team today.”

The Rays still own the American League’s best record by a half-game over the White Sox heading into Wednesday’s series finale. They’ll look to bounce back with a crisper overall effort than what they put together on Tuesday.

Left-hander Shane McClanahan worked five innings after failing to get through the fourth in his last two outings, but he couldn’t totally contain a White Sox lineup that has beaten up on lefties over the past two years. Since the start of last season, Chicago is 31-4 when its opponent starts a left-handed pitcher, the best record in the Majors in games over that span.

McClanahan seemed to attack the strike zone better than he did in his prior outings, striking out four with only one walk, and he induced 16 swinging strikes. But he still struggled to get ahead of hitters, throwing first-pitch strikes to only nine of the 23 he faced.

“I felt a lot better in the zone today, aside from first-pitch strikes. So that's obviously something that needs to be better,” McClanahan said. “I think I've done a good job so far this year of controlling the 0-0 count, getting to 0-1, but tonight's just one of those nights it didn't go my way.”

Two of the three runs McClanahan allowed came on an extremely rare misplay in the fourth inning by the Rays’ stingy defense. McClanahan walked Andrew Vaughn with one out, then gave up an infield single to Leury García. With two outs, Danny Mendick hit a single to left. Randy Arozarena picked it up and fired an on-target throw home, but it skipped through catcher Francisco Mejía’s legs, allowing Vaughn to score. Then McClanahan was admittedly caught off guard when the ball slipped past Mejía, leaving him out of position and allowing García to hustle home.

“It was a great throw from Randy, tough play for Frankie, and that's just how it rolls sometimes,” McClanahan said. “Frankie tried his hardest. That's just how it is. Tough play.”

Adam Engel led off the fifth with a solo shot to left-center, giving Keuchel more than enough breathing room. The veteran lefty limited the Rays to only four hits and one walk in seven innings. Keuchel was on top of his game, limiting hard contact and working efficiently, and Tampa Bay went 0-for-7 in its few chances with runners in scoring position.

For all the things the Rays have done well this season, they are still searching for more consistency against left-handers. They ended the night batting just .222/.303/.370 against lefties on the year, with a .673 OPS that ranked 24th in the Majors.

Despite that, Tampa Bay has managed to beat a handful of tough lefties by engineering late-inning comebacks. It looked like the Rays might have another one up their sleeve on Tuesday, as they brought the tying run to the plate against Liam Hendriks, but Brandon Lowe and Joey Wendle went down swinging to bring a trying day to an unusually quiet end.

“The offense has just been on a tremendous roll. The team's been on a great roll,” Cash said. “And I think, yes, [a rare shutout] shows how good our offense has been, and it also speaks to what Dallas Keuchel and their relievers did. They threw the ball really well between Keuchel to [Aaron] Bummer, and then we all know how good Hendriks is. I mean, those guys are tough.”