Corey Seager is banging on the door in Triple-A

As the 2015 season heads into the All-Star break, some players on the waiver wire are poised for big fantasy second halves.

Ownership numbers are in ESPN Leagues as of Saturday. 

Corey Seager – SS – Los Angeles Dodgers – 20.5 percent owned 

It’s not exactly clear when Seager is going to come up to the big leagues, but the top prospect is giving the Dodgers little choice but to call him up sometime this summer.

Despite being just 21 years old, Seager has already shown some advanced skills and put up good numbers at every level. After posting a eye-popping 196 wRC+ over 20 games of Double-A to begin the season, Los Angeles moved Seager to Triple-A Oklahoma City, where he has posted a solid .278/.328/.460 line in 59 games.

Seager runs an excellent strikeout rate and has shown some pop, blasting 13 home runs between the two levels. Meanwhile, Jimmy Rollins has posted -0.4 WAR as the primary shortstop for a team that is definitely in win-now mode.

Owners who need an immediate upgrade at shortstop should look elsewhere, as it may be another month or so before Seager joins the Dodgers. But Seager can provide massive upside for those with an open bench spot. He will surely get scooped up quickly when he does get the call.

Nick Castellanos – 3B – Detroit Tigers – 16.9 percent owned

Castellanos has largely been a disappointment in his first year and a half in the majors due to his billing as a top prospect and strong numbers in the minors. Fortunately, there are some signs that Castellanos may be turning things around, which could help a Tigers’ team that needs a spark and fantasy owners alike.

After a very poor start to the season, Castellanos has hit well since June 21, raising his season OPS from .594 to .667. The most encouraging sign came earlier this week in a series against the Seattle Mariners, as Castellanos hit two home runs after well over a month without one.

It’s easy to forget that Castellanos is just 23 years old and posted an impressive .307 ISO at Triple-A, so there’s definitely still potential for him to become a productive fantasy player. He’ll get plenty of opportunities to better his counting stats in Detroit’s lineup and could be a sneaky good acquisition for fantasy benches in the second half.

Wei-Yin Chen – SP – Baltimore Orioles – 40.6 percent owned

While it’s rare for a Baltimore starter to become fantasy relevant with such an extreme hitter’s park, Chen has consistently posted strong start after strong start.

Chen is continuing a pattern of improving every year since coming to the majors in 2012, posting a 2.82 ERA and 20.2 percent strikeout rate in his first 16 starts this season. Those numbers have been fueled by a recent hot streak, as Chen has not allowed two or more earned runs over a period of six straight starts.

There just aren’t many better options available in most leagues in terms of fantasy points per start than Chen. He’s a rare waiver wire option that is both proven and productive.

Manny Banuelos – RP – Atlanta Braves – 12.1 percent owned

While Banuelos is listed as a relief pitcher, he’s going to get the opportunity to start in Atlanta for the time being and has the raw talent to be an interesting fantasy prospect moving forward.

Once an extremely hyped prospect, Banuelos fell off the radar after undergoing Tommy John surgery in 2013 as a member of the New York Yankees organization. Now with the Atlanta Braves, Banuelos’ first two career starts have gone very well, as he allowed just one run on seven hits and three walks with eight strikeouts in 11 innings.

Banuelos has a nice mix of plus off-speed pitches and is continuing to show improved control as he gets further away from surgery. He’s got the upside to hold a rotation spot and be a solid streaming candidate.

Nathaniel Reeves is a correspondent at FantasyPros. To read more from Nathaniel, check out his archive and follow him @njr3701.