With the first half of the season fast approaching in A-ball, the traditional “mid-season” shuffle of minor league prospects is right around the corner.  This is when minor leaguers who have been impressive over the first two months of the season get promoted to the next level.  Some guys in the Mets system may have deserved a promotion before the halfway point, but the new front office is sticking by their policy of not rushing players up the ladder.  Also, both a-ball clubs are in the mist of chasing after a first-half division title that will clinch a playoff birth, so it’s important to keep those key players around a little longer.  Let’s take a look at the prospects that will soon be moving on up the farm system on their way to the big leagues: SAVANNAH TO ST. LUCIE:Greg Peavey RHP – He’s been good all season, and clearly ready for the next level, posting a 3.13 ERA in 13 starts.  The Florida State League should be a fitting challenge for last year’s 6th round draft pick.Josh Edgin LHP – This lefty has been dominant.  He is second in the Sally with 15 saves (even after being bumped from the role temporarily in favor of Ronny Morla).  In 29 innings he has struck out 39, allowed 13 hits and has a 0.93 ERA.  Righties are hitting .123 against him.Chase Huchingson LHP – Thirty teams and 50 rounds, and no one drafted this lefty with a 6’5’’ frame last year.  Huchingson now has the lowest ERA in the Sally at 1.97.  He has been equally effective as both a starter and reliever.Taylor Whitenton RHP – This may not be a guarantee to happen, but after a year and a half in Savannah, Whitenton should be ready for the FSL.  His ERA is more than a point less than what it was last year, and his walk and strikeout rates have also improved.  He’s been roughed up a couple times, but outside of that he has been effective, and deserves a promotion.Cory Vaughn OF – This is a no brainer.  Everyone has been clamoring for it (some even before the season), and now it should happen.  Regardless of whether or not he should have been moved sooner, we should learn a good deal from Vaughn playing the second half in St. Lucie.Robbie Shields SS – He should be ready for the move, but there’s no guarantee it will happen.  Age wise he should already be there, but Tommy John surgery held him back.  Now it’s logistics that is holding him back with top prospect Wilmer Flores playing shortstop in St. Lucie.  If the Mets want to move him to second base on a more permanent basis after a few games there for Savannah, there should be room for him in St. Lucie, but they’ve been reluctant to do that thus far because of the surgery, so we’ll see.ST. LUCIE TO BINGHAMTON:Matt Harvey RHP – It didn’t take long for Harvey to look ready for AA, and soon he’ll get his chance.  He is 8-2 with a 2.44 ERA in 13 starts, and his strikeout rate has increased over his last 4 starts.  He is certainly capable of continuing that kind of dominance in AA.Darin Gorski LHP – No one saw this coming.  In 63 innings, he has struck out 76, and posted a 1.72 ERA.  Gorski is a big lefty who added some velocity and is now having a lot of success.  In his last 4 outings, he has lasted at least 7 innings and given up a total of 3 runs.  It will be interesting to see how he fares in AA.Nick Carr RHP – He was drafted in 2005, and had Tommy John surgery in 2009, so he’s been around a while, but finally seems ready for the upper levels.  Carr has always had great velocity, but has struggled with control until this year.  In 22 innings, he has struck out 30 and has a WHIP of 1.14.  If he can pitch just as well for Binghamton, he could be on his way.Matt Den Dekker OF – Another guy that could have been promoted earlier, but there’s no harm done in spending a couple months in St. Lucie.  After leading the FSL in triples and being close to the top in doubles, Den Dekker is ready for AA.Juan Lagares & Pedro Zapata OF – There’s no guarantee that both guys will be on the move, but they both deserve it.  Both are among the top 10 in average in the FSL, and both are having great seasons and have been integral to St. Lucie’s success.   Lagares especially has been in the organization a long time and deserves a chance to move to the upper levels.BINGHAMTON TO BUFFALO:Josh Satin 2B – Satin deserves a promotion to Buffalo more than anybody (although for the record, no one else in Binghamton is deserving of one at all).  Satin carried the B-Mets offense for much of the first half, and he has hit at every level he has played.  Now at age 26, it’s time to move Satin to AAA.  With Reese Havens healthy, time at second base for Satin will be hard to come by.  The Mets are running out of reasons not promote him.BUFFALO TO NEW YORK:The Mets have taken so much from the Bisons already, there’s really nothing left to take.  Even Chris Schwinden, who may be at the top of the depth chart for a spot in the rotation, has been mediocre as of late.  The Mets won’t be in a hurry to bring anyone from the Bisons up to the big leagues unless absolutely necessary.