A few days ago, a reader asked for my thoughts regarding Boston Red Sox outfielder Jackie Bradley, Jr. My initial reply was along the lines of the typical butt-covering "obviously playing well but need more data and I haven't watched enough Red Sox games lately to say more," to which the reader responded "yeah, I know, but what do you THINK will happen? Just give an opinion ."
Well, okay then. Let's do this in back-of-the-envelope bullet point manner.
***With the recent hot streak (.333/.409/.667 since the All-Star Break), Bradley is now hitting .286/.366/.563 in 126 at-bats on the season with 16 walks and 39 strikeouts. Intuitively the .563 SLG seems higher than we should expect over a larger period, but the batting average and OBP are not outside the realm of what Bradley was supposed to be when he was a prospect. He was generally projected to be a guy who would hit in the .250-.270 range with a good OBP and slightly above-average power. His career line in Triple-A is .281/.365/.451.
***Alternatively, you could just look at his total big league line over parts of three seasons, which conveniently enough adds up to 675 plate appearances, 605 at-bats, right around "one season" worth of play. The total career slash is an unpleasant .215/.290/.339, which just goes to show how much of a hole he dug for himself last year. His career fWAR over that "season" is 2.0, 1.8 of which was generated just this year.
Again, he'd dug himself a big hole.
***Sources who follow the Red Sox closely think Bradley has made real changes both objectively and subjectively. A couple of weeks ago, Matthew Kory at Fangraphs explored the changes Bradley has made in his swing recently. In addition, Rob Bradford at WEEI noted yesterday that Bradley has made mental and emotional changes as well, feeling more comfortable and confident in the big league environment now.
It is always difficult (if not impossible) to untangle exact chains of causality in such cases, but the fact that observable mechanical and psychological changes coincide with the burst in production makes it less likely that it is merely a small sample fluke and more likely to be a result of actual growth and development.
***Of course, the key now is maintaining such changes over time and making any additional necessary adaptions once the pitchers start making counter-adjustments.
***With all that stuff in mind, my opinion is that the power production will slip over time and his SLG will get down into the .440-.450 territory, still solid but not as hot as he currently is. In the long run I expect him to settle in with major league numbers close to his Triple-A numbers, say .270-.280/.350-.360/.440-.450. Combine that with his excellent defense and you have an above-average regular and a consistent source of positive WAR value.
Red Sox fans and close observers may have a completely different opinion. Please share them and we can compare to these back-of-the-envelope bullet points.