Finally, he concluded the call must have been from John Farrell, the newly hired manager of the Red Sox.
Considering that Colbrunn had spent the past six years with the Yankees' Class A Charleston affiliate while Farrell had been the Red Sox's pitching coach and Blue Jays' manager, the connection between the two was distant. Colbrunn had no idea why Farrell was calling.
Farrell, though, offered Colbrunn a job as hitting coach for the Red Sox. It was quite the promotion.
"I had no idea," Colbrunn said. "That came as a shock."
But Farrell was sure he had the right man.
Farrell was just as sure when he decided on a pitching coach, hiring Juan Nieves, who had spent five years as bullpen coach for the White Sox. Dana LeVangie was hired as bullpen coach after spending seven seasons as a Red Sox scout.
Third-base coach Brian Butterfield and bench coach Torey Lovullo came over with Farrell from Toronto. First-base coach Arnie Beyeler was promoted after leading Triple-A Pawtucket to a Governor's Cup title and Minor League hitting coordinator Victor Rodriguez was also promoted, becoming assistant hitting coach.
The coaches came from all over. Some knew Farrell well, some hardly knew him. They had been carefully selected by the man in charge. And the man in charge had too much work to do.
"That's why our interview process in constructing a staff was exhaustive," Farrell said. "To get the right guys and then give them the freedom to do their job. We all share an expectation of what we want to get across to our players. And then to step back and let them go do their work, to me, is the only way to go about it."
Colbrunn and Rodriguez helped the Red Sox lead the Majors in runs (853), OBP (.349) and OPS (.795). They helped Will Middlebrooks break out of a two-month slump and ensured Mike Carp never had one.
Rodriguez already had an understanding of the Red Sox's hitting prospects.
"You can't count out Victor Rodriguez," Middlebrooks said. "He's someone I came up with all through the Minor Leagues. He was a hitting coordinator the whole time I was in the Minor Leagues. He knows me and knows my approach and is one of the ones who helped create an approach for me."
And Colbrunn understood how to work with veterans.
Carp, who had a .654 OPS with the Mariners last year, struggled at the plate in Spring Training with the Red Sox. That was the last time he struggled this season, as he posted an .885 OPS over 216 at-bats, many of which came off the bench.
"All year long it's been an amazing run," Carp said. "I've been pretty consistent. I don't know how that even happened, coming off the bench and doing some of the things I did. It was just a dream season."
Nieves was just as surprised as Colbrunn when he got the job.
"All the road trips, all the bus rides, they all paid off," Nieves said. "When a guy like John, who has been proven as a big league pitching coach, gives you a job, I think it raises the bar."
The Red Sox were, by most accounts, lucky to avoid major injuries this season. The three season-ending injuries they did suffer came from relievers Joel Hanrahan, Andrew Bailey and Andrew Miller.
And somehow the Red Sox bullpen got better.
Brandon Workman and Drake Britton, who started the season in Double-A Portland, turned into legitimate Major League relievers. Craig Breslow and Koji Uehara had the best seasons of their careers.
"You talk about it in football, that there's a system where the parts are replaceable," Breslow said. "We've kind of created a system here where, while we had all that turnover in the bullpen, the next guy was able to pick up where the previous guy was because that information was made available to them in a simple way that was easy to process."
Nieves is different from Farrell, and that's why it works.
"When Farrell speaks, it seems like he's been reciting it for two weeks before he says it," catcher Jarrod Saltalamacchia said. "Where Juan, he's more of a baseball guy. It's hard to explain. He talks like a baseball player would talk right now, where Farrell talks like, OK, he's been in the front office, he's been through scouting, he's been through coaching, he's now been through managing. So he's gotten all that into one, where Juan has been in the bullpen and this is his first pitching-coach job.
"I think you have to have like four different personalities. You need to have a hitting coach to remind a manager, 'Hey, this is what hitters are thinking and going through.' You need to have a pitching coach there to tell the manager, 'Hey this is what a pitcher, a bullpen goes through,' because sometimes you can forget this game's not easy.
"As a manager, sometimes you want things to go perfectly and you kind of forget that [Dustin Pedroia] has played 50 games in a row. He's tired. He might not be able to do this like he normally would. So having that group like that is what helps."
Farrell doesn't know everything about his team. Collectively, the men he chose to lead underneath him might.
Whether the Red Sox win the World Series, their coaching staff has been deemed a good one. Lovullo is considered a strong managerial candidate this offseason. Others may follow.
"You're already reading Torey's name," Farrell said. "He's already interviewed not only here in Boston but L.A. in the past. I think he's a manager in waiting. It's a matter of time for him. Brian Butterfield has interviewed in the past, as well. We've got multiple candidates, I think, current and future, that can realize their professional goal, being a manager as well."