Miller scored 19 points and No. 2 Kentucky routed Portland 87-63 on Saturday night in the Wildcats' final tuneup before playing St. John's and No. 1 North Carolina next week.
Terrence Jones also scored 19 points and Anthony Davis added 13 points, 12 rebounds and four blocks, but Miller started 37 of 38 games last year and his senior presence has steadied a team filled with sophomores and freshmen.
"Michael Gilchrist came into me and said if I need to come in off the bench for Darius, I will. I have absolutely no problem," said Kentucky coach John Calipari, who will consider putting Miller back in the lineup over the next four days.
Kidd-Gilchrist said he respects Miller's leadership and the 6-foot-8 swingman is the key to the Wildcats. But Miller said his role doesn't matter.
"I'm not really worried about coming off the bench or starting or whatever," Miller said. "We don't have time to worry about that. We've got a lot of things we need to correct before we try to make a run at a national championship."
Kentucky (6-0) has won every game by double digits, but Portland gave the Wildcats plenty to work on in the coming days after the Pilots (2-4) challenged them with sharp outside shooting and won the rebounding battle, 39-38.
"We gave up a lot of points off 3s, that's one thing we can work on, really trailing the screens," Jones said.
Kentucky used an 18-3 first-half run to take a double-digit lead. After Portland pulled within six in the second half, the Wildcats put on a full-court press as part of an 18-4 run that put the game out of reach.
Nemanja Mitrovic went 6 of 12 from 3-point range and finished with 20 points for the Pilots.
Calipari said Friday he wanted the Wildcats to play more fluid without him having to call plays from the sideline before next week's tough games. Kentucky responded with its most efficient game so far, committing just four turnovers, its fewest since committing just two in a win against Utah in the second round of the 1993 NCAA tournament.
The Pilots trailed by 12 at halftime, but put together a run in the second half. Mitrovic hit his fifth 3-pointer, Thomas van der Mars went up strong over Davis and Dorian Cason hit a free throw to trim the Wildcats' lead to 43-37.
"Earlier in the week, I had to break it to them that Kentucky was a little more athletic," Portland coach Eric Reveno said. "We had to beat them with toughness and skill, and we weren't able to do that consistently."
After a timeout, Kentucky came out with a full-court press that flustered Portland. Cason threw the ball away to Jones, who started the fast break by finding Marquis Teague. Teague feathered a touch pass toward the rim that Davis finished for the alley-oop dunk.
Then Tanner Riley committed a turnover and Kidd-Gilchrist slammed it over Derrick Rodgers as part of a three-point play that made it 50-37. A few minutes later, Miller's 3-pointer gave Kentucky its first 20-point lead.
Teague finished with 14 points, eight assists and no turnovers while Kidd-Gilchrist had 13 points. Portland's Riley scored 14 and Tim Douglas added 12.
Kentucky now has several days to prepare for Thursday night's matchup with the Red Storm before playing the Tar Heels in the final of a series of hyped early season matchups next week that also includes big out-of-conference games between Duke-Ohio State, Florida-Syracuse and Vanderbilt-Louisville.
"We know it's going to be two really tough games," Miller said. "Especially St. John's, North Carolina, they're two of the elite teams in the nation. I think both of them are really good."
Kentucky's big first-half run made it 31-15 and featured several different Wildcats. Kidd-Gilchrist found Davis on a lob for a dunk, Miller hit a 3-pointer and Jones added a 3 of his own before slashing to the rim for a layup.
But the Pilots stayed within striking distance by hitting 3s. Mitrovic and Riley had three each in the first half, and Riley's third cut it to 34-26 with 1:03 left before Kentucky scored the final four points of the half.
Mitrovic shot 46 percent from 3-point range last year, one of the best marks in the country, but made just nine over Portland's first five games.
"We didn't want to come out and back down at all," Mitrovic said. "We just came out firing and stayed in there with them for a little while."