Here was the hometown kid, a day after earning a starting role, living the dream as he struggled to sip a cup of water in the dugout after hitting the go-ahead home run exactly one week after being called up to the Majors.
"I'm really at a loss of words," Walker said afterward. "And I'm usually not at a loss of words."
Tough to blame the Pittsburgh product.
Walker's first Major League home run, a two-run dinger to left in the eighth inning, provided the Pirates the lift they needed Tuesday night in a 3-2 win over the Cubs before 11,334 at PNC Park.
It came on an 0-1 pitch from Ted Lilly after he walked Andrew McCutchen on four pitches, which prompted Cubs manager Lou Piniella to come out to meet with his lefty.
But the skipper left Lilly in, and on his 103rd pitch of the night, an 87-mph fastball, Walker ripped one into the left-field stands. That allowed the Pine-Richland graduate to live out the same scene he imagined as far back as a 5-year-old T-ball player.
"Really blurry -- really was," Walker said of rounding the bases. "Just my first thought was we took the lead, and I was real happy. And by the time I hit home and saw Andrew, a guy that I've gone five or six years playing with ... and all the stuff we've gone through together, it gave me chills. And to see the guys in the dugout and how happy they were was great."
It came after a tense 7 1/2 innings, marred by an ex-Pirate's bat and a costly baserunning gaffe.
Xavier Nady, who was part of the Pirates' trade that landed them Jeff Karstens two years ago, went 4-for-4, finishing a triple shy of the cycle.
After Kosuke Fukudome led off the third with a triple, Nady smacked Karstens' 81-mph slider over the left-field wall in the third inning to make it 2-0.
Karstens led off the next frame with a single but couldn't help his cause three batters later. With two outs, Lastings Milledge ripped a 2-2 sinker to left-center that fell just out of the reach of center fielder Tyler Colvin. Alfonso Soriano retrieved the ball and relayed to shortstop Starlin Castro, who was able to throw out Milledge at third before Karstens jogged home, ending the inning and negating the run.
"Lastings made a big mistake," Pirates manager John Russell said. "He should have just stayed at second base. The pitcher is in front of him, we had the run, and his job was done. He got excited and the excitement and adrenaline took over. His brain didn't really take over at that point. He's got to stop at second, knowing that the pitcher is in front of him. It should have been a run."
"I didn't run hard," Karstens said. "I ran hard around second and around third and then thought I had it easily."
Garrett Jones made up for it an inning later, lifting a 2-2 changeup to right for a leadoff home run, cutting the Cubs' lead in half. The homer was the Harvey, Ill., native's seventh of the season and his second in as many days. The right-fielder is now 14-for-30 in eight games against the Cubs this season.
"Being from Chicago, I guess, maybe pumps me up a little bit," Jones said. "I grew up a [White] Sox fan, so maybe there's something down deep there."
Karstens, meanwhile, recovered from the missed opportunity to allow just one hit over the next three innings. The right-hander connected on 66 of his 104 pitches for strikes over six innings, the Nady homer serving as the only runs Chicago scored off him. Karstens struck out three and walked three.
The win was the Pirates' seventh in eight games against the Cubs this season, an oddity that resonates with their players' numbers.
Take Jones, whose last three homers and 12 of his 32 RBIs on the season have come against them.
Or closer Octavio Dotel, who struck out two in a perfect ninth to pick up his 12th save of the season, five of which have come against the Cubs.
And then there's Walker, whose first career home run came against the team the Pirates have owned this season, in front of his mom, dad and girlfriend, no less.
The dinger earned him the game's scorecard -- which he plans to frame -- and the home run ball.
After a postgame pie to the face from winning pitcher Joel Hanrahan, it might have cost him some eyewear.
"The pie didn't feel so good -- my eyes, I think my contacts are going to have to go after this one," Walker said. "But it was a special day. They could have thrown hot sauce on my face, and I still would have been all right with this."
Matt Fortuna is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.