For close to 45 minutes, Clemens, accompanied by agent Randy Hendricks, set up shop in a small office in front of the clubhouse and talked with Red Sox general manager Theo Epstein. Principal owner John W. Henry also stopped in, as did chairman Tom Werner.
Josh Beckett's eyes lit up when he saw the Rocket, and he also went in to speak with the fellow hard thrower and Texas native. Tim Wakefield, David Ortiz and Trot Nixon were among the Boston players who exchanged pleasantries with the legendary Rocket.
So was the World Baseball Classic truly a swan song for a certain future Hall of Famer, or does he still have some pitches left in that lightning bolt of an arm?
"I don't have any interest in playing right now, at all," said Clemens. "Again, like I said guys, I kind of get on Randy [Hendricks] all the time, he's making this more and more difficult to retire. That's his job, he just lays my options out there if it happens. Again, I'm probably going to kick back and watch. If somebody goes down, or something like that, and I really feel like I can help and get out there and contribute, I might decide to do it. But not at this point."
If Clemens chooses to play baseball again, the Red Sox are still one of the four teams he would consider, along with the Rangers, Yankees and Astros.
Epstein and Henry flew to Houston to meet with Clemens during the winter, and Werner used his Hollywood roots to produce a poignant video that the club presented to their once franchise icon.
"It was just a great video. It had a little bit of everything, it had a lot of the fans around the city ," said Clemens. "It brought back a lot of memories and I got to see the young me. I've aged."
Maybe by way of appearance, but hardly from a pitching standpoint. All he did for the Astros in 2005 was post a 1.87 ERA and lead them to the World Series.
How much is nostalgia tugging at him to give it one last try in the place his legend began?
"Obviously, Boston is one of the teams I have a fondness for. It's really a home for me," said Clemens. "The other three teams are in the situation ... really every stop that I've been at, they've been great for me and I feel like I've in turn given them every bit of my effort. Again, I told Theo, I'm going to come up and watch a game or two before the summer gets too long and basically just get out of these guys' way."
Clemens, who has always consulted his family when it comes to his career, said that they'd warm to a return to Boston if that's what he chose to do.
"I can tell you that my two little ones are even warming up to that," Clemens said. "They're starting to make comments now that baseball season is getting under way. You can ask Deb, she had tears in her eyes watching the video they brought down, too. Boston is very special to us, no doubt about it."
Special enough to give up the comfort of retirement for another long grind through a baseball season? That is the question Clemens just can't answer at this point.
"If it works out and I can just fade away, that's what's gonna happen," he said. "And I'm good with it, maybe that will happen where I can sit back and enjoy and watch some ballgames. Again, I put myself under a lot of stress and my body under a lot of stress, because as you guys know, I want to perform. I don't like it at all when I don't perform. And that's the bottom line. They don't care how old I am or what I do if I end up coming back and playing with a club. They're going to want me to perform."
He has been impressed by his dealings with the Red Sox, a team that has a completely new front office and ownership than when he last pitched for the club.
"[Epstein] gets to the point, John Henry, the same thing, I totally understand it," Clemens said. "Like I said, it would be a huge commitment on my part, also. They're making a great commitment, and I appreciate it very much. Theo just said, 'I appreciate you coming by, I know you have decisions to make and we don't want to force your hand, but we're ready to talk if that door opens.' "
There are still some reminders of Rocket's past in the Boston clubhouse. First-base coach Bill Haselman caught the second 20-strikeout game of his career, in September 1996, against the Tigers. Al Nipper, one of Clemens' closest friends in baseball, is the interim pitching coach for the Red Sox this season as Dave Wallace bounces back from hip woes. And Wakefield, a Rocket rotation mate in his first Boston go-around, is still going strong.
"It was great to see Nip. I sat with Nip and Wake last night for a long time and talked with them," said Clemens.
The No. 21 that Clemens wore during his 13 years in a Boston uniform has stayed inactive since his departure. The 192 victories that were tied with Cy Young atop the team's all-time list when he left remain just one victory from moving to sole possession of first on the team's win list.
"Every one of these teams independently makes sense," said Hendricks. "That's the interesting part. But I think they make more sense if they're playing very well and he decides to play. Boston would be a completion of his cycle. We all realize that. Part of me thinks about win No. 193 so that we can have the players win the Roger Clemens Award instead of the Cy Young Award.
"It definitely is in the back of his head. It definitely is in the back of my mind, too. I think one of the big issues between the Red Sox and Yankees is just the incredible rivalry that exists between the two cities and the two teams. That's it own conundrum right there. You sit down and say, 'Boy, those both make a lot of sense. Where do you go? Someone's going to be really unhappy.' So that's a factor there. It's not so intense down here. In fact, it's probably about 20 percent as intense. But still, that's the Houston-Dallas thing down here."
Hendricks said that there is no specific timetable that Clemens would have to return by, but felt that the All-Star break would be about the longest he could wait.
With uncertainty still swirling in his mind, Clemens made his way to the stands, where he watched Opening Day as a non-uniformed spectator for the first time in more than two decades.
"It's Opening Day and I'm going to put a golf visor on and I'm going to enjoy a ballgame," said Clemens.
If Clemens decides to change his mind, the Red Sox undoubtedly will have a cap and uniform waiting for him.