It is harder to learn about a young player in September, when rosters are skewed by the addition of minor-league players and most games are rendered insignificant, but then Clayton Kershaw stood on the Citizens Bank Park mound in the sixth inning.
"You try to make it just another game," Aaron Altherr said afterward, "but deep down you know it's really not because of how good he is and how good he's been over the years. He's a future Hall of Famer."
Altherr came to the plate in a 4-3 Phillies' win over Los Angeles with the bases loaded after Rhys Hoskins drew a seven-pitch walk. Kershaw, the best pitcher on the planet, ditched his trademark curveball and chucked a slider that lacked movement. It was the 104th time in his career that Kershaw faced a batter with the bases loaded.
And Altherr was the first to hang a grand slam on him.
"I definitely don't take it for granted," Altherr said.
The ball landed in the second deck in left field. Altherr circled the bases and bashed arms with Hoskins to celebrate. A half-filled ballpark demanded more. They greeted Chase Utley in Dodger blue with a prolonged standing ovation earlier in the night, but Utley is the past. Altherr emerged for a curtain call and acknowledged the crowd with a wave.
It was Game 150, another night for one of the worst teams in baseball, and it did not feel meaningless — not to a young lineup trying to establish its merit.
Kershaw entered with a 2.12 ERA. The Dodgers were 21-3 in his 24 starts. He opposed a Phillies lineup that averaged 25 years of age. That is how Phillies manager Pete Mackanin wanted it.
"You want to play in the big leagues, let's play in the big leagues," Mackanin said before the game. "We don't want platoon players. We want everyday players."
So Nick Williams and Hoskins and Altherr formed the middle of the lineup. Williams struck out on four pitches in the sixth inning before Hoskins, stuck in a mini-slump, walked to the plate. Hoskins spoiled one of Kershaw's looping curveballs to keep the at-bat alive. It was quiet enough to hear Kershaw's grunt as he threw a 2-2 pitch for ball three. Hoskins did not bite on a full-count slider, low for ball four.
Then, Altherr struck with his 17th home run. The whole night changed in the span of 10 pitches that left Kershaw befuddled.
"Everyone is full of energy," Mackanin said, "and it's a lot of fun going down the stretch."
The Phillies flaunted their youth all night. Nick Pivetta, 24, surrendered two home runs on his first five pitches of the game. But he recovered to limit the first-place Dodgers to two runs in six innings. J.P. Crawford, 22, impressed with a barehanded grab to retire Yasiel Puig in the eighth inning. Victor Arano, 22, was entrusted with two key outs in the seventh inning.
For promising hitters like Hoskins and Williams, tests against the better pitchers in baseball can provide some of the finer lessons. Hoskins singled in two at-bats and walked against Kershaw. The rookie is now 2 for 13 with eight strikeouts and four walks against Kershaw, Jacob deGrom, Max Scherzer, Stephen Strasburg and Madison Bumgarner. Williams is 5 for 20 with eight strikeouts against the same group of five National League aces.
One day, Hoskins and Williams could face those pitchers with a little more at stake. They will have some previous experience to apply to the next encounter, like Altherr did. Kershaw jammed him in his first two at-bats, a groundout and a soft line out.
"I was just telling myself not to get beat," Altherr said.
The 26-year-old outfielder swung and missed at the first pitch. He took the next one for a ball. Altherr looked for a pitch on the inner half. Kershaw put it there. It landed 418 feet from home plate, and Altherr will never forget it.