The recent history of extraordinary Red Sox spring performances suggests that what transpires in March does very little to illuminate what a player might do when the curtain lifts on the season. Perhaps no player better illustrates that notion than Jackie Bradley Jr., who looked like an emerging star in 2013 spring training and forced his way onto the team’s Opening Day roster. Once in the majors that year, he couldn’t find his way to the Mendoza Line.

His take on the value of spring training performance?

“I guess everybody’s different. As always, it depends,” said Bradley. “[But] the only games that matter are the ones during the season. [Spring training is] more about getting the body back into a baseball-conditioned state.”

Will Middlebrooks likewise starred in the spring of 2014, appearing on the cusp of a breakout in Florida only to spend that season in a career-altering downward spiral of injury and diminished production.

Indeed, of the 22 Red Sox players who hit .350 or better in at least 40 spring training at-bats over the 10 years from 2006-15, a case can be made that just two – Jacoby Ellsbury in 2011 and Alex Cora in 2008 – meaningfully outperformed what might have been considered reasonable career projections based on age and track record in the absence of those spring performances. Meanwhile, there are plenty of cases of players (Mike Napoli in 2015, Jeremy Hermida in 2010, J.D. Drew in 2007, Coco Crisp in 2006) who had brilliant springs but then underperformed their track records in the regular season.

All of that being the case, there’s a bit of danger for the Red Sox in making a significant decision on the division of their positional playing time based on what they’re seeing in the spring. What Shaw has done both in the big leagues in 2015 and during an up-and-down trajectory through the minors prior to that should matter quite a bit more than his Grapefruit League production.

If the Sox were considering him as a player who might supplant Pablo Sandoval or Hanley Ramirez prior to the start of the spring – a not-unreasonable possibility – then perhaps they can give some small weight to his excellent performance to this point. But if the team entered spring believing that Shaw should be a versatile backup behind Sandoval, Ramirez, and Rusney Castillo in left, then even if he hits a home run in every remaining at-bat in Florida, it makes little sense for the team to alter its outlook.

“What you have to do is take a spring training evaluation in context of what has happened prior as well,” said manager John Farrell. “In some cases, spring training will be a determining factor, if you’ve got head-up competition. You also look at how a given hitter is addressing different types of pitches in the strike zone, how they’re managing an at-bat or working a count, rather than the flip side being just an aggressive, free swinging and things are just falling in. You look at all things inside of a given at-bat, and the contact ability, bat-to-ball ability with different spots in the strike zone, that’s as telling as what the end result might be.”

Yet sometimes, even that is insufficient to help with projections. The spring is, in many ways, a reality unto itself, predictive of so little when the games start to count.

Follow Alex Speier on Twitter at @alexspeier.