KANSAS CITY — The weirdest part of all of this for Jon Lester? The color scheme.

For a dozen years, his work clothes came in the understated reds and blues of the Red Sox, and they fit his low-key personality. The stitched B might be iconic, but the colors themselves don’t exactly pop. Boston’s grey and blue road uniform wouldn’t look out of place in a prison.

As Lester lounged in his new uniform on Monday, however, the juxtaposition couldn’t have been more jarring.

“And then you go to green and yellow,” he said, looking down. “That’s different.”

Those would be the colors of the Oakland A’s, and they’re practically day-glo by comparison. Lester won’t be wearing them for very long, but he should get used to green, because wherever he ends up this winter, he’ll be swimming in it.

Lester has done nothing to hurt his cause in free agency since the July 31 deal that rocked baseball. He has won his first three starts after last night’s victory over the Royals (see Page 50), and remains in the midst of his best season, with a chance to earn legitimate Cy Young consideration over the final six weeks.

Not even two weeks into Lester’s tenure with the A’s, two things are apparent. One is that he has welcomed a respite from the daily grind of contract questions that he handled with such aplomb in Boston. The other is that the Red Sox remain very much in his thoughts.

“I literally went from basically every single day answering questions about my contract to, I haven’t had one question about it,” Lester said in the visiting clubhouse at Kauffman Stadium. “Not one. That’s been nice. Like I told you guys in spring and throughout the year, you’re the elephant in the room. It’s on everybody’s mind, it’s a topic every single day. No matter how well or bad you answer it, and no matter what the front office does or doesn’t say, it’s going to be a topic. I knew that. You couldn’t get mad at it. I understood it.”

Now he understands what awaits him. His time in Oakland will be short — “It’s going to be two months, or hopefully three, build some good relationships, and then shake hands and go our separate ways,” he said — and then it’s on to the great unknown of free agency, where he will be one of the most sought after players on the market.

The Sox have made it clear they want him back, though it remains to be seen how far they’ll extend themselves.

Lester would welcome a return.

“My time there, the memories and all that stuff don’t get erased based on this whole ordeal,” Lester said. “I’m glad with where I’m at, and I understood where Ben (Cherington) was at. At the end of the season, it’s not going to change my mind about going back there if they are aggressive and competitive and do the things they say they’re going to do. Boston is definitely a place I would go.”

Be aggressive

The Red Sox haven’t wavered from the stance that they’d like Lester back. Since he departed, team sources have insisted the club will pursue him “aggressively.”

Whether their definition of the term jibes with Lester’s is up for debate, since the two sides never advanced far beyond Boston’s opening offer of four years for $70 million this spring. We’ll never know if a proposal of, say, five years and $100 million would’ve locked up Lester in March — he doesn’t like hypotheticals — but he knows the impression owner John Henry left in their final conversation after he cleaned out his locker.

“They told me, ‘We’re going to be aggressive. You’re going to get blown out of the water by some of these (other) offers,’ ” Lester recalled. “I’m like, ‘I don’t need to be blown out of the water.’ Why would I need to be blown out of the water? That doesn’t make or break your decision, at least for me. I’m not going to the highest bidder. I’m going to the place that makes me and my family happy. If that’s Boston, it’s Boston.”

Lester is not looking to set contract records, even though it wouldn’t be surprising to see him earn an offer of least six years and $150 million.

“In the greater scheme of things, we’re talking about just a stupid amount of money,” he said. “For me, I want to be comfortable. The way I look at it is, if someone gives you $170 million and someone gives you $150 million, is that $20 million really going to change your lifestyle? Same thing if the highest bidder is $100 million and the team you’re going to feel most comfortable with offers $80 million. Is that $20 million really going to make the difference in your lifestyle?”

If these two weeks in Oakland have reminded him of anything, it’s that he can adapt to new surroundings.

“Change is sometimes good,” Lester said. “For me, it was good to see what’s out there. The transition’s been pretty easy so far. It’s like changing schools. You go to the next grade, meet a bunch of new people, and feel your way through a couple of weeks of awkwardness. I always knew I could (adapt), it was just a matter of not wanting to.”

Which brings us back to Boston. When he hears the team say it plans to step to the plate, he sounds hopeful, to an extent.

“That’s exciting to hear,” he said. “But at the same time, we need to get to that point, and then we’ll see.”

Fitting in

In the meantime, Lester finds himself in a position unfamiliar to virtually all of his ex-teammates, with a chance to win another World Series.

The A’s have owned the game’s best record for most of the season, and their Lester-fronted staff is one of the deepest in the game, including fellow acquisition Jeff Samardzija, as well as All-Star Scott Kazmir and rising young right-hander Sonny Gray.

The A’s reacted like everyone else when news of Lester’s acquisition broke.

“Complete shock,” said former Red Sox outfielder Josh Reddick. “I woke up and my phone was blowing up and I turned on the news and saw it and my jaw just dropped. For someone to come over from the worst team in their division to the best team in baseball has to be a great change for him. Granted, that’s the organization he grew up in and knows, but I don’t think you can be too upset leaving a team like that for a place where your chances are still very high of going back-to-back as world champions.”

Closer Sean Doolittle said Lester’s arrival signified management’s willingness to go for broke.

“When we made the trade for (Jason) Hammel and Samardzija, our starting staff already had the best ERA in baseball,” Doolittle said. “Then when you get Jon Lester, the best left-hander in baseball, you’re going all in.”

Clayton Kershaw might have something to say about that, but regardless, the A’s got a taste of Lester’s playoff-style intensity in his second start, when he took a no-hitter into the sixth against the Twins en route to a 3-0 shutout.

“He was at (105) pitches after the eighth, and I knew there was no way I was getting loose to come into that game,” Doolittle said. “That was his game and he was going to finish what he started.”

Lester jokes that the transition has been eased by all the “nimwits” he played with in Boston, from Brandon Moss to Reddick to Jed Lowrie to Nick Punto to Coco Crisp. Curt Young was his pitching coach for a year in Boston. And bringing Jonny Gomes west with him helped, too.

The adjustment has been toughest on his family. He’s living with his wife, Farrah, and two sons in a rented house. Lester’s parents have come down from Washington to help. His 4-year-old, Hudson, recently asked Doolittle if he pitched for the Red Sox.

“He thinks the house we’re staying in is a cool hotel for the weekend,” Lester said. “He wants to know when we’re going home. So that’s hard.”

Lester still owns a house in Newton and will return in the offseason to gather his things. How much longer he calls it home is in the court of the Red Sox.

“I want to be happy,” he said. “I want my family to be happy. I want to be comfortable. If that means taking less money, it means taking less money. If it means going to the highest bidder, it means going to the highest bidder, but that’s not going to dictate where I’ll be happy.”

And as for his house?

“We’ll hold onto it a little longer. See what happens.”