Mid-season call-ups are a fantasy owner's dream. Those prospects you followed throughout spring training and have been waiting too see in action will soon get the chance to prove themselves. The problem is that everyone else is waiting for the exact same thing. Smart owners will have to decide which prospects to target and when to act. While not all prospects pan out, adding that one who becomes an instant star can be a difference-maker in deep leagues.

The following list will help you fill gaps in your lineup or add stream-worthy players to your NL-only roster. Whether you are targeting a specific position to upgrade, or a certain category to improve, there is likely an available player or two that can help out. The following players are owned in 25% or less of Fleaflicker leagues.

Editor’s Note: to read about even more waiver wire options, be sure to check out our famous waiver wire pickups list which is a running list that is updated daily. Prefer using your phone? Our free waiver wire app is available for download in the Apple & Android Stores.

National League Waiver Wire Pickups

Hitters

Trea Turner (2B/SS, WAS) - 9% owned - May 30th is the magical day when the Nationals may suddenly change their mind about promoting Turner to the big club. Without getting too detailed, after May 30th, the Nats retain his rights for another full year. If he's ready to play at the Major League level, there would be nothing holding him back from taking over shortstop other than Danny Espinosa. Turner is slashing .324/.384/.479 with 17 RBI and 14 SB in Triple-A Syracuse this season. If (when) he takes over as an everyday player for Washington, he will immediately have value in mixed leagues as well. In other words, pick him up now.

Tommy Joseph (C, PHI) - 1% owned - Joseph will be filling in at first base for the Phillies in a temporary platoon with Ryan Howard. Joseph was on fire in the minors, hitting .347 with six homers and 17 RBI. The Phillies hope he can provide an offensive spark that is badly needed for the second-lowest scoring team in baseball. He chipped in his first MLB homer on Tuesday against the Marlins, so he is off to a good start. With catcher eligibility, Joseph becomes an interesting speculative pick for deep single leagues. Chances are most owners aren't rushing to pick him up just yet, so follow his progress this week to see if he has anything to offer at the top level of competition before adding him.

Jose Peraza (2B, CIN) - 3% owned - Another rookie call-up that may or may not be temporary, Peraza will play center field for the time being. Naturally a second baseman, his path is blocked by Brandon Phillips at the moment. When Billy Hamilton returns later this week, Peraza may very well find himself back in the minors. Considering the Reds are not overflowing with MLB-ready talent, however, it wouldn't be surprising to see him stick on the bench or at another position. Hamilton has been injury and slump prone in the past. Peraza may only be worth starting this week, but his speed makes him stash-worthy if you have the room.

Melvin Upton Jr. (OF, SD) - 14% owned - It hasn't happened yet. Those waiting for Melvin to become bad BJ again might be disappointed to know that the senior Upton is still hitting well and out-producing little brother by far. Upton is up to five homers, 16 RBI and seven steals on the season. He has already matched his output from all of 2015 and is on pace for a 20/20 season. The .281 average will likely drop, but that's not why you own BJ... I mean, Melvin Upton Jr. in the first place. He should be starting in all single leagues at this point.

Yasmani Grandal (C, LAD) - 20% owned - The last three games notwithstanding, Grandal had been picking up the pace offensively. He has two homers and five runs batted in over the past week. Most importantly, he remains healthy and should be a dependable backstop for the Dodgers. Few catchers this season possess 20 HR upside like he does. If you're tired of streaming different catchers week in and week out, Grandal should get you similar, if not better production from other available options.

Chris Herrmann (C, ARI) - 4% owned - Another former Hurricanes catcher makes this list. Herrmann has received some time behind the plate lately, filling in for Wellington Castillo. He's made the most of that time, hitting .419 with two HR and 10 RBI in his past eight starts. Although Castillo had a hot April, he has cooled off a bit, so Herrmann should continue to receive spot starts. Herrmann even received a start in CF the other day, as manager Chip Hale is not hesitant to put players at different positions to keep them in the lineup. Herrmann won't be an everyday catcher unless something happens to Castillo, but much like Brandon Drury, he will keep playing somewhere as long as he's hitting.

Kirk Nieuwenhuis (OF, MIL) - 1% owned - This former Met didn't want Aaron Hill and Alex Presley to be the only "has-beens" to suddenly produce in Milwaukee. Nieuwenhuis is quietly having a productive season for the Brew Crew, although his playing time has been inconsistent. His .275 average is nothing spectacular, but he has driven in 12 runs in only 69 at-bats. He may only appeal to owners in the deepest of NL leagues, but considering the disappointing performance of Milwaukee outfielders not named Ryan Braun, he has a chance to see increased playing time.

Jose Reyes (SS, COL) - 24% owned - Reyes barely makes the cut-off here as many owners have been stashing him in hopes of a mid-season return. That return is officially coming May 31, although he will likely need some time in the minors to get back in game shape first. The only question here is whether he will remain in the National League upon return. It's obvious he isn't getting the job in Colorado back thanks to some guy named Story, but several teams are interested in trading for him. If he latches on somewhere else in the NL, he could be a quality starter by mid-June. If you're willing to roll the dice, now's the time to stash him on your bench if he's available.

Pitchers

Jon Gray (SP, COL) - 10% owned - Don't be scared of Gray because of the uniform he wears. Despite three consecutive quality starts, one of them a seven-inning, one-hit performance, Gray's ownership remains ridiculously low. This former third overall pick has the stuff to excel in the majors. His 11.3 K/9 alone gives him great value. Looking at his 2.33 FIP and 1.7% HR% should be enough to assure owners that his performance won't be deterred by the thin Colorado air. He belongs on rosters in mixed leagues at this point. If you're in an NL-only league and he is available, don't hesitate any longer.

Alex Wood (SP, LAD) - 22% owned - Wood was a fantasy sleeper in Atlanta who provided starting value at a bargain cost. His transition to Los Angeles hasn't gone so well, however, as he hasn't kept his ERA under four since arriving last year. He is not a high strikeout volume pitcher, so he will need to display good control to keep his ratios down in order to retain fantasy value. He had a rough start, but over the last two games he has allowed a total of two earned runs on seven hits in a combined 12.1 innings. Those two starts were against the Mets and Cardinals, quality opponents. Maybe it's a sign he is turning the corner.

Tony Cingrani (CIN, SP/RP) - 4% owned - Somebody has to close the game when Cincinnati actually wins. Cingrani still seems to be that man until further notice. He has not inspired much confidence, blowing two out of five save opportunities. If you are in desperate need of saves, you may be able to squeeze a few out of him while he retains the job. With no obvious replacement, Cingrani could stick as the closer until he implodes. If you are willing to take the chance, there are likely not many other closing options available right now.

Matt Wisler (ATL, SP) - 12% owned - Wisler really needs to get more love considering his performance this season. His 0.99 WHIP places him in the Top 10 among all MLB qualified starters. He only has one win to show for it, but he has thrown five quality starts in seven attempts. His 5.9 K/9 leaves something to be desired, but those ratios are too good to ignore. Wisler is cemented as the Braves' #2 starter, which is not necessarily a bragging point, but he should be a consistent starter all season.

Mike Foltynewicz (ATL, SP) - % owned - To recommend putting Foltynewicz in your lineup, it is advisable to ignore his MLB record up to this point. If you look at his track record, you might be scared by his career 5.23 ERA and 1.56 WHIP. If you focus on his last two starts of this season, you might see a 25-year-old who is 6'4" and throws 96 MPH suddenly putting it all together at the top level. He threw eight scoreless against Kansas City, which followed a seven-inning, two-run effort against Arizona. Folty has the tools, it's just a matter of whether he can show consistency.

Christian Friedrich (SD, SP) - % owned - Speaking of track records, you really don't want to know Friedrich's numbers, not even in the minors. Here they are anyway: 5-16, 5.66 ERA, 1.60 WHIP in MLB action. 21-35, 4.52 ERA, 1.39 WHIP in the minors. His spot start and surprising success last Friday aren't necessarily a sign of things to come. It might actually be more of a reflection on how bad the Brewers are than how good Friedrich will be. Regardless, if you are desperate for pitching and want to throw a dart his way, maybe Friedrich will continue to surprise.

Jeremy Hellickson (SP, PHI) - 6% owned - Of all the Phillies young starters who are pleasantly surprising, it is the veteran Hellickson whose performance has possibly been the most surprising. He hadn't finished a season with less than 4.50 ERA in four years, but he is at 4.12 right now. His 46 strikeouts in 43.2 innings are keeping his value up. Despite the winning record (3-2), don't expect a ton of wins in Philly. Hellickson can provide solid, if not spectacular numbers at the back end of your rotation.

Hunter Strickland (RP, SF) - 7% owned - The closer role in San Francisco has been Santiago Casilla's, but his grip on the job seems tenuous. Most agree that Strickland is a closer-in-waiting with his higher velocity and 9.53 K/9. He is yet to record a save this season or last season either, but it seems just a matter of time. Strickland can help owners in need of relief help by providing Ks and the occasional hold, but is really more of a stash right now in case the Giants switch gears in the bullpen. After all, it's hard to find a good closer these days.

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