Wednesday's 9-1 loss is the latest in a series of struggles Robertson has been having virtually all season. Forget about those struggles for a moment, however, and the latest outing is plenty to tackle in itself.
Just two Tigers in the last 53 years had served up five home runs in a game, none since the Red Sox put up five homers on Jeff Weaver July 24, 1999, at Tiger Stadium. Don Mossi was the other, in 1961.
All eight hits off Robertson went for extra bases, making Robertson just the seventh Major League pitcher since 1956 to give up five homers and no singles in a game, according to research on Baseball-Reference.com and Retrosheet.org. In that same span, only Florida's Ricky Nolasco has given up more hits in a game without yielding a single, allowing nine over 4 2/3 innings on April 17 of this season.
Add that damage to Robertson's stats to date, though, and his ERA jumped back over the 6.00 mark, to 6.09, second-highest among Major League pitchers with enough innings to qualify for an ERA title behind Seattle's Carlos Silva. Opponents' slugging percentage against the left-hander is up to .533, bettering only the .538 clip against Cincinnati's Aaron Harang for highest in the Majors.
By itself, Wednesday's outing could be brushed off in part to a night of bad pitches in a park where the ball can fly. Wednesday's game-time temperature was 75 degrees, well below normal for Texas this time of year, but the humidity remained high after late-afternoon rains.
"No place is a place for pitches in those areas," manager Jim Leyland said, "but this place is really dangerous. That's basically what happened."
Still, the stats of a summer-long struggle put the outing into context, and put both Robertson and the Tigers in a position of searching for answers on what to do. What wasn't evident in the stats was clear on the look on Robertson's face as he manned the mound.
"My slider was off tonight," Robertson said, "and it's been very inconsistent all year long. It's not doing much. It just spins, stays up and gets whacked."
Leyland did not want to discuss any decisions after the game, but he said he wants to check with Robertson and the team medical staff about his health and other potential clues. Robertson has said he's healthy up to this point, and Leyland said he doesn't think there's an injury. Still, he has to check.
"I'm going to look into it," Leyland said, "see if there's a problem somewhere, if there's something physically going on that I don't know about. I don't know. I'll look into it, because he's having a tough time. You don't like to see anybody get hit like that. You just don't."
That sentiment was echoed.
"I feel for him a lot," catcher Brandon Inge said. "When you go through a year like this, every single thing seems to compound your thoughts on how bad the year's going. Believe me, I've been there."
Like Robertson, Inge struggled his first season after signing a lucrative multi-year contract.
"You just got the contract and you feel like you're letting the team down," Inge said. "I understand how he's feeling. I've been through it. He's a good pitcher, and this is just a spell he's going through. It's a tough year for him, and hopefully he can put it right behind him and keep moving on."
The home run portion of the barrage began with Travis Metcalf's two-run drive to left to open the scoring in the second inning, driving in Marlon Byrd, who reached base after Edgar Renteria had dropped his popup behind second base. Metcalf entered Wednesday batting .158 (6-for-38) for the season, including 3-for-23 against left-handed pitchers, but he pounced on an inside fastball that caught too much of the plate and was left waist-high.
Brandon Boggs and Michael Young, both batting right-handed, hit back-to-back blasts to lead off the third inning. Both were opposite-field shots to right field -- Boggs on a hanging slider off the plate, Young on a fastball. Josh Hamilton and Milton Bradley delivered their knockout combination in the fourth.
Hamilton's 29th home run of the season traveled an estimated 402 feet to right field before Bradley swung and missed at Robertson's next pitch, the second and final swing-and-miss Robertson induced in his outing. Bradley made up for it by driving the next pitch 430 feet to center.
That was it for Robertson, who gave up eight runs (six earned) over 3 2/3 innings with four walks. Metcalf added his second homer of the game with a seventh-inning shot off reliever Aquilino Lopez.
Fourth-inning doubles from Ramon Santiago and Miguel Cabrera accounted for Detroit's lone run off starter Kevin Millwood (7-7), who went the distance on a six-hitter.
Jason Beck is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.