The question is whether Bay will walk back in that same door for Opening Day of next season. The star run producer is eligible for free agency, and with the Red Sox now out of the postseason, Bay will start mulling his future.
Boston general manager Theo Epstein made it clear on Monday that the team would like to have Bay patrolling left field and occupying a high-impact spot in the middle of the batting order for next season and beyond.
"We've had a lot of discussion with this representative through the course of the last nine months, and most of it has been under the radar screen and underreported even after the fact, so we'll just continue that and try our best to work something out confidentially," Epstein said. "He's a pro and we have a lot of respect for him and what's he's done since we acquired him. You couldn't have asked more from him since the day he put on a Red Sox uniform, and that's a good thing too, since we traded a pretty good player for him. We want the relationship to continue, so we'll see if it does."
While Bay admitted he has to view the market in a more broad sense, he also indicated he would welcome a chance to return to Boston, a place he is adapted to seamlessly both on and off the field.
"I think ultimately it just boils down to the fact that I've gotten to this point and I'd be doing myself a disservice if I didn't look around," said Bay. "But at the same time, I've said it all along -- I'm a pretty level-headed guy. If something comes along that makes sense [with the Red Sox], I'd have a tough time saying no."
The Red Sox have exclusive negotiating rights with Bay until 15 days after the World Series. However, it is rare for a free agent not to at least explore the market.
There have been times in the past where the Red Sox have made the calculated risk to allow players to become free agents before trying to get them re-signed. When it comes to Bay, Epstein wanted to get it done before it got to that. In-season negotiations ended at the All-Star break.
"It's been a really unusual negotiation in the first place, so I can't tell you what's going to happen," said Epstein. "We want to keep him and he wants to stay here and we've been unable to reach a deal. I don't think either side has been unreasonable or too conservative or not aggressive enough, not pro-active enough.
"It just hasn't happened and it's been disappointing that it hasn't. I don't think he's to blame for it. I don't think we're to blame for it. It still hasn't happened. I hope it does. And if that [exclusivity] period can help bring the sides together, then great. And if it doesn't, then we'll see what happens."
In the final two months of 2008, after being acquired for Manny Ramirez, Bay batted .293 with nine homers and 37 RBIs in 49 games for Boston.
This season, he hit .267 with 36 homers, 119 RBIs, while producing a .921 OPS (on-base plus slugging).
What has Bay enjoyed most about his time in Boston?
"For me, it's been the winning," Bay said. "You get that in some other places. But after being here, the rabid fan base and playing for the Red Sox, there's really not that experience in a lot of places. When I got here, baseball, not that it wasn't fun before, but it was really fun again. I kind of enjoyed that."
Now, he has to weigh everything out to decide whether he stays in Boston or moves on. Bay and his family live in Seattle during the offseason.
"At some point, it is about the money. It's not all about the money," Bay said. "The situation I was in before I came here, in Pittsburgh, we weren't winning a lot of ballgames, and then you come here and you get to win ballgames and go to the playoffs two years in a row, that is a huge factor in it. It really makes baseball enjoyable again.
"A lot has been made because I live in Seattle -- this whole West Coast thing. That would be a positive for those teams, but at the same time, I'm comfortable. I've been here, knowing the guys, knowing the team, knowing everything, definitely makes it more desirable than a lot of other places."
While some free agents have a specific time frame in mind of when they'd like to sign, Bay would prefer to keep his options open.
"I don't know. I haven't given it a ton of thought," Bay said. "I don't even know exactly when [free agency] starts. I don't know what's going on. I get to go home and let my agent take care of it and chime in, but I'm definitely excited to see what goes on."
If Bay does return to the Red Sox, he can start next season with a comfort level that, obviously, won't be there if he goes elsewhere.
"I'm a creature of habit," said Bay. "I like already knowing the guys in the clubhouse, knowing Tito, knowing what it's like to play here. I really enjoyed it. The familiarity is huge."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.