Starting in 2014 the Rays went to heat-pressed set tags with QR barcodes for their game-used stuff. I know I bought a Kiermaier team-issued jersey last year from MLB auctions which had #39, and did not have this barcode. My best guess was that this was one he wore in 2013, or during a time he was not on the active roster (Not sure how much he hung around the team last year during his rehab from the wrist injury).