The Marlins have designated right-hander Jacob Turner for assignment, the club announced. Lefty Brian Flynn has been recalled to take his spot on the active roster.

Needless to say, this comes as something of a surprise. Turner, 23, was at one point considered by some to be one of the game’s twenty best prospects. And while he has not produced good bottom-line results this year (5.97 ERA), Turner has been victimized by a .368 BABIP. And he has thrown just 264 total big league innings over parts of the last four seasons.

Notably, he has improved significantly this year in several respects: his 6.2 K/9 and 2.6 BB/9 are improvements over last year, even though he’s allowed more earned runs, and he has even bumped up his groundball rate to 51.3%. Indeed, Turner owns a 4.01 FIP, 3.93 xFIP, and 3.98 SIERA on the season — all career-low marks, and all seemingly in line with a player of his age and former repute. His fastball velocity is on the rise.

Turner’s situation will certainly warrant a close eye. He will, of course, need to pass through waivers to be dealt. One wonders whether Miami perhaps already has its eye on some sort of trade with a high waiver-priority club. (The Rockies, followed by the Cubs, Phillies, and Diamondbacks, currently lead the NL “reverse standings.”) It is hard to imagine the club simply letting him go: not only was Turner the key piece in the deal that sent Anibal Sanchez and Omar Infante to the Tigers two years ago (which also included Flynn), but he came into the season with just 1.033 years of service to his credit and so will not even be arb-eligible until 2016.

It is worth noting that Turner is already out of options and is playing on a MLB contract, which he signed after being chosen ninth overall in the 2009 draft. That deal comes with a $1MM option for next year. It gave Turner the right to opt out of that salary and file for arbitration if eligible after this season, but he won’t have enough service time to qualify. Nevertheless, the lack of an available option does limit his market somewhat, as a team would need to be willing to use both a 40-man and an active roster spot (or try to slip him through outright waivers at an opportune moment).

The fact is, players like Turner have value, even if they have not lived up to expectations. He reached the big leagues at a young age, and it seems that several teams would be willing to hold an active roster spot for him to make a run at harnessing his potential (while reaping the benefits of his low salary and team control). Just last year, the Astros shipped a very similar player in Jordan Lyles — former top prospect, decent peripherals, poor results — to the Rockies (along with Brandon Barnes) to acquire two full seasons of a solid, reasonably affordable MLB center fielder in Dexter Fowler.

On the other hand, Turner is something of an extraneous part for Miami, which has other advanced young arms in its system. (One contributing factor to that assessment, however, is that the team recently added Jarred Cosart via trade.) The club seems to be willing to give up at least some future value to improve its chances in 2014 — the Fish sit six and a half back in the NL East — and it could be that the assessment was already made that he would not warrant a roster spot for the rest of the way or over the offseason. (Of course, if that truly were the case, it would have seemed more likely for Turner to be moved a few days ago.)