By now, the debate about Stephen Strasburg's shutdown is irrelevant. The questions about why the Nationals handled him the way they did or whether it is right or wrong to shut down the staff ace in the midst of a postseason run no longer matter.

But one question still seems reasonable to ask: Why focus on innings pitched?

For all of Strasburg's impressive numbers this season -- 20 quality starts, 1.15 WHIP and 15 wins to go along with his National League-best 11.13 strikeouts per nine innings -- there's been one number that's followed Strasburg since before the Nats even broke camp: 160.

Washington employed a 160-inning limit with Jordan Zimmermann last year and has now cut off Strasburg at the 159 1/3 mark this season. But in an age where a player's value is measured through statistical acronyms such as WAR, BABIP, DIPS, SECA and ISOP (yes, those all exist), it'd seem as if there'd be something more advanced than the simple total innings pitched to evaluate the wear and tear on a pitcher's arm.

"We have a history on these type of rehabilitations, surgeries and how they get back to play a year after the Tommy John surgery," Nats general manager Mike Rizzo said. "We followed the protocol. We had parameters set in mind. After [Friday's] start, we just figured that mentally and physically, Stephen looked like he was fatigued. We decided, what's the difference of 159 1/3 innings or 163, four or 5 1/2 innings? We said, 'Let's pull the plug today, and we move on with the season and try to finish the season off positively.'"

Earlier this summer, Rizzo said he planned to use the "eye test" when it came to determining when to shut down Strasburg -- an exam the phenom apparently failed his last time out. The question has to remain, however, just how much other factors like total pitches or percentage of breaking balls come into play.

After all, wouldn't an 85-pitch outing over seven innings take less of a toll on a hurler's arm than getting roughed up for 95 pitches and yanked after five frames? In the books, it ends up as two fewer innings pitched, but it might leave that pitcher just a little worse off.

Then again, maybe those two extra innings of ramping it up on the mound then cooling down in the dugout has just as much of an effect as throwing 10 more pitches in two fewer innings of work.

"I have no idea. I'm a pitcher, not a scientist," said White Sox pitcher Chris Sale, who has also been monitored closely in his first season as a starter. "I don't know what it is or what it could be. I don't know what the diagnosis is or the science behind it or anything like that. I just try not to pay attention to any of that stuff. Just go out there and pitch and try to do my job."

That's one of the things that makes it all the more frustrating for someone in Strasburg's position -- he really has no control over it. While Strasburg -- and everyone else, for that matter -- has long known a shutdown was looming at some point this season, the 24-year-old right-hander certainly didn't want, nor did he expect, it to come on the heels of one of his worst outings.

Unfortunately, in Rizzo's eyes, getting lit up for five runs over three innings Friday and sitting just two outs shy of that 160-inning benchmark no longer qualifies as passing that post-Tommy John surgery eye test.

"I went through the same thing last year and left on a bad note," Zimmermann said. "I had to sit on that all offseason. It just makes you work harder and want to get back. I think he is taking it pretty hard. ... You can't look into it too much. They had the 160 mark set since however far back. You knew it was going to happen sooner or later. I thought he would get another crack at finishing [the season] strong. It is what it is, we'll move on."

So Strasburg finishes the year having tossed 2,607 pitches over 159 1/3 innings. Yet the Dodgers' Aaron Harang has recorded one less inning, but he has thrown 2,730 pitches.

There are some considerable variations between pitchers' total innings and total pitches marks all across the league. Take Indians starter Ubaldo Jimenez and Royals hurler Luke Hochevar, for instance.

Despite working an identical 161 1/3 innings, Jimenez has needed 2,839 pitches to do so, while Hochevar has thrown just 2,593. By Hochevar's 92.6 pitches per start average, the 246 pitches he's saved compared to Jimenez is the equivalent of another two-and-a-half starts.

Strasburg's total pitch count identically matches that of Sale, another pitcher whom many anticipated could be on an innings limit this year after his transition from the bullpen this spring. Now Sale obviously isn't coming off a Tommy John surgery like Strasburg, but the principle of nurturing a valuable young arm remains the same.

Though Sale has thrown the same amount of pitches and 9 2/3 more innings than Strasburg, there are still many moving parts to the equation. Take into account that 19 percent of Strasburg's pitches this year were curveballs, the 15th-highest curveball percentage of any qualified pitcher. On the same token, Sale has gone to his slider 25.9 percent of the time, the 13th-highest rate.

Obviously only time will tell whether this move benefits Strasburg in the long run or if the White Sox's approach with Sale ultimately hinders his career down the road. Either way, the current process is one that doesn't sit well with a competitor like Strasburg.

"It was pretty shocking. Honestly, I'm not too happy about it. I want to keep pitching out there," Strasburg said of the recently imposed shutdown. "But as of right now, I think we've got some world-renowned doctors, and one of them is Dr. [Lewis] Yocum. He resurrected my career, so I got to listen to him and I got to trust him."

With no sabermetric stat having being designed yet for handling a returning Tommy John patient, that's all a young pitcher can really do for now -- trust that all-encompassing subjective eye test.