Kobayashi, after sitting in the 'pen for seven innings Wednesday night, came out in the eighth to make his Major League debut against the White Sox.
It wasn't the most seamless of affairs. Kobayashi, who was signed to a two-year, $6 million contract over the winter, faced three batters, striking out Nick Swisher and giving up a pair of singles. Swisher only struck out because he swung at what might have been ball four in a 3-2 count.
Two American League scouts watching Kobayashi's outing said he lacked life on his slider, which is his supposed to be his out pitch.
"But it's his big league debut," one scout said. "May is the time to panic."
Pitching coach Carl Willis said Kobayashi, who maxed out at 91 mph, was overthrowing, which might have led to him missing his spots.
"It was good to get him in there with a bit of a cushion to get his feet wet," Willis said. "He'll be more settled the next time out."
Though he is hardly used to such arctic conditions, Kobayashi didn't make any excuses.
"It was cold for me, but it was cold for everybody," he said. "I didn't feel like it was unfair."
Anthony Castrovince is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.