Welcome to the Friday edition of The Cooler, where it's clear that some scars remain. Let's get to it:

*Twins rookie Luis Arraez had three more hits Thursday — a single, double and two-run homer that started the scoring in what became a comfortable 13-6 Twins win at Texas.

His numbers this season would be exceptional for just about anyone, but they are borderline ridiculous for a 22-year-old rookie: .355 average and .425 on-base percentage with just 14 strikeouts to go with 23 walks in 212 plate appearances.

Suffice to say his emergence has made a stacked lineup even deeper. And even if some of his production is not sustainable — as suggested by his current .368 batting average on balls in play — the fact that he's hitting with some pop (14 extra-base hits) bodes well for the future.

In the present, his start has earned some lofty statistical comparisons to some of the all-time greats. His .355 batting average, for instance, is higher than any rookie finished a season with (minimum 200 plate appearances) since 1950. And the names on that list are quite impressive.

Not only that, but he has more hits in his first 55 career games than all but three Twins. Again, an awfully good list.

*We were treated to a lesson in baseball's dumb/cryptic "unwritten rules" late in Thursday's blowout.

Twins batter Jake Cave swung at a 3-0 pitch and laced it for a single in the top of the ninth, with the Twins up 13-5. Apparently that's a no-no because, I don't know, when you're winning you're supposed to stop trying?

Twins TV play-by-play man Dick Bremer picked up on it immediately, and Cave was shown trying to apologize for it.

Max Kepler, the next Twins hitter, reached a 3-0 count … and then was drilled in the shoulder by Rangers pitcher Shawn Kelley — a pretty obvious retaliation for this unwritten rule violation. The Twins broadcast even praised Kelley for being professional about where he plunked Kepler.

Grow up, baseball.

*Bryce Harper mashed a walk-off grand slam for the Phillies in a 7-5 win over the Cubs on Thursday, the biggest hit of the season with his new team.

But if you're wondering if he hit it off Craig Kimbrel … no, he did not. The object of Twins fans affection has been on the injured list since Aug. 3. He should be back soon, with hopes of improving on his 0-2 record and 5.68 ERA.