At least one of baseball’s unwritten rules is time sensitive, broken out only in the final days or weeks of a season, primarily by managers of mediocre teams. It’s an issue of sportsmanship-based lineup construction, hinging on the fact that simply because your team has little to play for, the opposition isn’t necessarily in the same boat.

Which leads to differing points of view. Does a manager field his best players when facing teams still in the playoff hunt, as a courtesy to those they’re battling for postseason berths, or can he keep trotting out prospects, the better to gauge what he’ll have to work with next season?

Mariners manager Lloyd McClendon is firmly in the former camp, playing his regular starters in this week’s series against the playoff-hungry Astros at Safeco Field. (Little matter; Houston took two of three.)

Elsewhere in the American League West, however, things played out differently. Last week the A’s called up Barry Zito for a nostalgia-heavy, swan-song start against Tim Hudson and the Giants. The lefty getting shelled for six hits and four runs over two innings made little difference to the big picture, what with both teams effectively out of the playoff chase.

When Zito’s turn came around yesterday, however, there he was again, making what was likely his final major league start. This time, however, his opponent was the Angels, battling Houston for a wild card spot. The Astros had just come off of three games against Seattle’s best (discounting the fingernail issue that sidelined James Paxton and Taijuan Walker’s innings limit, which would likely have sidelined both even had Seattle had something to play for), and now their primary opponent for a playoff berth got to tee off against Zito?

Houston manager A.J. Hinch took things in stride. “Anybody at this level deserves to be here in my eye,” he said in the Houston Chronicle. “You manage your own team and handle your own business.” (Zito gave up four hits and four walks over four innings, but the Angels only scored twice against him and the A’s ended up winning, 8-7.)

Teams aren’t always as forgiving as Hinch. From a post I wrote in 2011:

In 2004, going into the season’s final series, the Giants and Houston were tied for the wild card lead with 89-70 records. The Astros closed with three home games against Colorado, while the Giants visited Los Angeles.

Suffice it to say that members of the San Francisco clubhouse took note when Rockies manager Clint Hurdle trotted out a series-opening lineup featuring six rookies—Aaron Miles, Clint Barmes, Garrett Atkins, Jorge Piedra, Brad Hawpe and JD Closser.

The Giants managed to take two of three from the Dodgers, but it wasn’t enough; the Astros swept punchless Colorado.

“All we needed was for Houston to lose one game,” said then-Giants reliever Matt Herges. “We were watching that, yelling, ‘This is a joke.’ We couldn’t stand Clint Hurdle after that.”

Hurdle wasn’t alone in his thinking. (“Goddammit, if I’m that far out of the pennant race, the players I was playing weren’t worth a shit, anyway,” Jim Leyland told me when he was managing the Tigers. “You might as well take a chance and look at some new players for next year.”) Still, the majority opinion holds that such situations are best avoided. Hurdle got an extra look at a bunch of prospects, at a very real cost to the pennant race. McClendon could have spent the games against Houston evaluating prospects for next year, but recognized that he still has three more games against Oakland with which to do that.

And no, Barry Zito will not start any of them.