BOSTON -- After throwing six innings on Friday night in St. Louis -- and exiting with his team ahead -- the Pirates' James McDonald learned that he wasn't the only Major League pitcher in the family anymore.

Darnell McDonald, the fifth outfielder for the Red Sox, also learned a lesson on Friday: his cousin's job isn't all that easy.

After Darnell allowed two runs and four baserunners in the ninth inning of a 15-5 loss to the A's on Friday night, the takeaway he had from the outing was exactly the lesson James said he would try to impress on his cousin when they next speak.

"Really, it was a lot tougher than it looks," said Darnell, who twice reached 90 mph on the gun and threw 24 pitches, 11 for strikes. "Trying to throw strikes, I was a little wild early on. Couldn't find my release point. You know, a couple more bullpen sessions with [pitching coach Curt Young], I'll be ready for the playoffs."

James, the younger of the two at 26, is 8-6 with a 4.22 ERA for Pittsburgh. He took a no-decision in St. Louis' 5-4 win.

The 32-year-old Darnell -- whose brother Donzell was also a Major Leaguer -- said he hadn't pitched since high school, but that didn't mean the raw ability isn't there. He was the 1997 Baseball America High School Player of the Year, and said he can climb above 90 mph if he uses his legs better. He did, indeed, check the gun on the mound.

Darnell's first pitch to Oakland's Scott Sizemore sailed to the backstop, but he was just glad it didn't sail inside the batter's box. The advice he got before going to the mound was simple: "Don't throw any breaking balls, just lob it in there, but once the adrenaline kicks in, see the miles per hour up there, try to let it go a little bit," he said. "I really just didn't want to hit somebody. I would've felt bad if I reared back and hit somebody in the face."

The first two hitters of the inning walked on 10 pitches before Darnell settled in. He threw a first-pitch strike to Ryan Sweeney and got a lazy fly to left for the first out two pitches later, then got a groundout from Hideki Matsui. Josh Willingham didn't get all of the two-run double to left that he hit, instead getting some help on a sky-high fly from the Green Monster. Another groundout ended the inning.

At the time of Willingham's double, Darnell said he was trying to work on his sinker.

"We were able to get out of the inning," he said. "It's too bad I gave up a couple of runs, but now I'm official. I'm officially a pitcher."

Darnell said he talked about taking the mound before, but made clear those conversations were never serious. His opportunity arose because the Red Sox have a doubleheader on Saturday, and wanted to keep their regular arms fresh.

"I just wanted Mac to try to throw strikes and to try to save [Franklin] Morales was our next option, and he's been up or in five or six of the last seven nights," manager Terry Francona said. "We didn't want to do that. With two games [Saturday], because Mac was able to go out there, maybe we have a better chance of winning the game [Saturday]."

Darnell called the opportunity "once in a lifetime," but if he gets another chance, he does want a little help from James.

Said Darnell: "He's got to show me how to throw that curveball that he has."