But when the Red Sox asked McDonald to fly from Rochester, N.Y., (where Triple-A Pawtucket was playing) to Boston on Tuesday in the event that they might need to put him on the roster, how was he supposed to know it would evolve into the most storybook evening of his career?
Less than 90 minutes before the game started, the Red Sox finally summoned McDonald from a nearby hotel to Fenway Park. Jacoby Ellsbury's batting-practice session did not go well, so the speedy left fielder went on the disabled list with a left chest contusion.
Enter McDonald, who was called on by manager Terry Francona in the bottom of the eighth, the reeling Red Sox trailing by two runs. Stepping in as a pinch-hitter for Josh Reddick, the other player promoted from Pawtucket on Tuesday, McDonald promptly belted a game-tying two-run homer over the Green Monster.
He was just getting started. The night -- and the game -- ended with McDonald clubbing a walk-off single off the Monster with two outs in the bottom of the ninth. Just like that, it was Red Sox 7, Rangers 6.
"Well, I got on the plane today and was sitting around [waiting]," said McDonald. "I came to the field, pretty much put my uniform on and got ready for the game. I couldn't write a script any better than this. A lot happened real quick tonight. It was a dream come true. That's the reason I signed over here, to play in this type of atmosphere, to play for an organization like this."
The Red Sox liked what they saw from the 31-year-old McDonald in Spring Training and felt that, at some point, he might help them against left-handed pitching.
"He's a great kid," Francona said. "Again, early in Spring Training, he was hurt and he wasn't able to play, so he had to go back to the Minor League complex and do his rehab. You give him that speech: 'Go to Triple-A, play well and we'll call you up.' That's what he did. And he impacts the first game he plays with us and helps us win."
According to the Elias Sports Bureau, McDonald is the first Red Sox player to end a game with an RBI hit in his debut with the team since RBIs were first kept as a stat in 1920.
And by clocking a home run in his first plate appearance, McDonald became the first Boston hitter to do that since Orlando Cabrera on Aug. 1, 2004.
"He's the microwave -- instant offense," beamed Red Sox second baseman Dustin Pedroia. "There's no more Vinnie Johnson. Darnell McDonald. He's the Microwave, OK?"
Whatever works. The Red Sox just needed the win.
"Darnell was awesome for us," Pedroia said. "We needed that spark, and when he got in the game, he brought a lot of energy. Game-tying home run, he won the game for us and he gave us a big lift."
While McDonald might have lifted the Red Sox, his teammates flattened him. As he took the turn around first after his parting shot, his teammates raced onto the field and mobbed him on the outfield grass beyond shortstop. Kevin Youkilis and Jonathan Papelbon were the leading pass rushers.
"Hopefully I'll be able to play tomorrow," quipped McDonald. "They beat me up pretty good. When I seen Papelbon running out there, I tried to run away, but somebody got a hold of me. I haven't been beat up like that in a long time. I'll take that kind of beating any day. They got me pretty good. My lip is kind of busted up a little bit."
It is the sweetest pain McDonald has felt in a long time. Way back when, he was a first-round selection by the Orioles in the 1997 First-Year Player Draft.
"For me, there was a lot of perseverance and hard work, and I just kept plugging along," McDonald said. "And to get to this point, I can't put it into words how much it means to me."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.