On Wednesday, he was back in the Tigers clubhouse. He was still relaxed, but his season might not be over just yet.
"I'm kind of on call. That's the best way to put it," Miller said Wednesday before the team worked out at Comerica Park. "And I really don't know much. All I know is I'm here and I need to continue to do what they tell me."
All manager Jim Leyland would tell reporters was short.
"That's a possible roster decision, depending on who we play," he said.
Whether it's a legitimate option or a smokescreen, it throws something out there to consider. The 21-year-old who was the sixth overall selection in the First-Year Player Draft back in June could go from pitching in the College World Series to pitching in the World Series in the same year, something nobody has done since at least the advent of the draft in 1965.
The possibility of adding Miller would seemingly be an answer in relief against the Mets, whose ability to alternate left-handed and right-handed hitters in their lineup could force Leyland to use more relievers for one hitter at a time in later innings than he did in the previous two rounds.
Carlos Delgado and Cliff Floyd are obvious left-handed power sources, but right-handed-hitting David Wright hit 46 points lower against lefties in the regular season -- including just .209 with two homers in 86 at-bats after the All-Star break. Switch-hitting Jose Valentin batted just .219 versus lefties with two homers in 96 at-bats. Even slick-hitting switch-hitter Jose Reyes, while punishing southpaws in most situations all year, went just 3-for-14 off of them in the late innings of close games in the regular season.
Should Miller be added to the roster over a right-handed pitcher, the Tigers bullpen would have three lefties and three righties before closer Todd Jones. Moreover, Miller is more of a power thrower than a typical lefty reliever. His fastball-slider combination gives opponents a different look than what they would see from Jamie Walker or even Wilfredo Ledezma.
To be effective against anybody, though, Miller has to throw the ball over the plate, something he didn't do well. He walked 10 batters over 10 1/3 innings in his stretch-run appearance, including seven of 16 left-handed batters he faced.
"Throwing strikes to everybody was a problem this year," Miller admitted. "Walks kill you. I knew that coming in and didn't do enough about it. It might've been a different experience if I hadn't walked nearly as many people, but you live and you learn."
Those command struggles, and the potential that he could be useful if he solved them, were apparently one reason why the Tigers sent him to instructional ball after the regular season ended. He worked with pitching instructor Jon Matlack there on his control before making three instructional starts, totaling six innings.
"Just ironed out some minor mechanical things, trying to make it simpler," Miller said. "The simpler you are, the easier it is to throw strikes and repeat your delivery."
Miller saw every Tigers playoff game on television and was amazed watching the celebration. The only downside on the day he watched the Tigers clinch the ALCS was his beloved Florida Gators' loss to Auburn in football a few hours later.
"I went from a real high to a low," he said. "But I think that one game in the middle of the season for Florida doesn't compare to winning the ALCS."
A World Series appearance, of course, would top all of that. He watched the Marlins win Game 5 of the 2003 World Series, but from the stands. Pitching in one, as incredible as it sounds, has been on his mind.
"They told me all along that that's why I was down there, to stay in shape," Miller said. "Now I'm here to continue staying in shape, I guess."
More workouts: Leyland characterized Wednesday's workout as a lot more detail-oriented than the improvised work they did Tuesday at Ford Field. They were back at Comerica Park, and they closed off the ballpark to the media as a precaution.
"We're going to have a real Spring Training workout today," he said beforehand. "It should be quite a bit more sophisticated than it was yesterday."
While there wasn't much to learn Tuesday, Leyland realized that not all of his players wanted the same amount of rest. Carlos Guillen, for one, told him his sore back would feel better if he's moving around every day.
So instead of giving a complete day off Thursday, he scheduled an optional workout. That way, players can either keep close to game shape or wrap up ticket obligations, family matters and other potential distractions before they all go back to work for Friday's formal workout.
Injury updates: Sean Casey did not participate at full strength in Tuesday's workout while dealing with his injured left calf, Leyland said.
"At some point, he's going to have to," Leyland said.
Casey is still expected to be healthy for Game 1 Saturday.
Joel Zumaya, meanwhile, rejoined the team Wednesday after missing Tuesday's workout with permission to spend time with his family in California. He said his right wrist is feeling well.
Jason Beck is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.