Relievers, by nature, are rather volatile assets, both in real life and in fantasy baseball.

There are very few relief pitchers who are locked into their role, and various things can force a change -- whether it be an unsuspected drop in effectiveness (i.e. Ken Giles), or a midseason trade that upends the role they had locked down on their previous team (see: Brad Hand and Jeurys Familia). That can make finding saves a tricky proposition in fantasy.

So, chances are you're looking for some saves (or holds, depending on your league), so here are a few relievers to add for the stretch run of the baseball season.

Héctor Rondón, Houston Astros (66% owned in Yahoo!)

Rondón certainly is not widely available, but there is little reason why he should be on 34% of waiver wires right now. He has a clear path to saves -- former closer Ken Giles was sent down to Triple-A on July 11th, and it seems as though he'll be down there for the foreseeable future. Rondón, in Giles' stead, has been incredible.

In 39 games this season, he has a 1.49 ERA (37 ERA-) and 1.84 FIP (45 FIP-). He has a solid walk rate at 7.5%, and he is also striking out batters at an excellent clip on top of it, registering a 32.2% strikeout rate this season. He has done an excellent job of keeping the ball on the ground (48.3% ground-ball rate), which has helped keep his fly-ball rate down (29.9%).

He is 9-for-10 in save opportunities this year, as he started to take away saves from Giles even before the latter's demotion. This move seemed to be in the cards before Giles was optioned to Triple-A, and now that Giles is gone, Rondón has a smooth path to saves for one of the best teams -- maybe the best team -- in baseball

Rondón looks like a lock for the Houston Astros' closer spot for the last few months of the season, and it looks like an excellent option for fantasy owners. He is striking out of a ton of batters and has been an extremely reliable reliever both in and out of save situations over the year. Now that he is getting save chances on a consistent basis, he looks like he will be extremely valuable down the stretch.

Jace Fry - Chicago White Sox (2% owned in Yahoo!)

The bullpen of the Chicago White Sox is in pretty rough shape now that Joakim Soria was traded to the Milwaukee Brewers. With Nate Jones out for the foreseeable future after having a setback while rehabbing, Jace Fry looks like the clear best bet to take the closer job.

Fry has a 3.86 ERA and 2.27 FIP, both above-average numbers (93 ERA-, 54 FIP-). He owns a 30.7% strikeout rate with a 9.7% walk rate. He has done a nice job of limiting hard contact (27.0%) and keeping the ball on the ground (42.9%).

He is a lefty, but the White Sox have not treated him as a lefty specialist as he has actually faced more right-handed hitters than lefties so far this year. Righties are better off of Fry, but their .241/.333/.339 slash line is hardly terrifying.

While the White Sox are bad, Soria was a rather good fantasy closer, notching 16 saves before his trade. With Jones out for the foreseeable future, the door seems wide open for saves for the White Sox, making Fry a worthwhile pickup.

Kirby Yates, San Diego Padres (51% owned in Yahoo!)

The San Diego Padres recently traded closer Brad Hand to the Cleveland Indians for quite the haul, but there is not necessarily an opening for the closer role in San Diego.

That's because it's Kirby Yates' job. Yates has been absolutely excellent this season and will be the closer (as long as he is not traded, as well). In 40 games this year, Yates has a minuscule 1.40 ERA (36 ERA-) and a 1.99 FIP (49 FIP-), and he has everything to back it up. His strikeout rate (32.9%) and walk rate (7.2%) are phenomenal.

When he is not striking out batters, he is getting them to hit the ball on the ground, as he has a ground-ball rate of 50.6%. Much like Rondón, his elevated ground-ball rate keeps his fly-ball rate low (28.7%), which helps keep the ball in the park.

Yates has been excellent (arguably better than Hand has been), and he has already taken the closer role in Hand's absence, getting a save against the New York Mets over the weekend. While the Padres are a bad team, Hand still managed to net 24 saves before his trade, good for seventh-best in baseball. They have clearly sustained a top-tier closer before, and it stands to reason that someone with numbers like Yates' can be very valuable down the stretch.

Brad Brach, Baltimore Orioles (48% owned in Yahoo!)

Zach Britton is no longer a Baltimore Oriole, so the closer job belongs to Brad Brach yet again.

Brach is no stranger to this role. Britton has not exactly been a pillar of health these past two seasons, as multiple forearm problems cost him time in 2017 and a ruptured Achilles saw him miss the first two months of the 2018 season before debuting in June. Brach has frequently slotted in as the closer in Britton's absence, raking up 29 saves over the past two seasons.

While opportunity and comfort are not a problem, Brach's current season certainly is. He has been rather unreliable all season, as he has a 4.85 ERA, and 4.00 FIP so far this year. His strikeout rate has dipped to a career-low 20.5%, and he is walking far too many batters (10.3%). He is getting hit hard, as his hard-hit rate sits at a career high 32.0%. There is a lot of bad stuff here with Brach.

But while Brach has certainly struggled this year, he has plenty of opportunity, and there is a long track record of him being a legitimately great reliever, so a return to form is not impossible to comprehend. He is a bit of a risky option, but he will be in line for saves nonetheless.

A.J. Minter, Atlanta Braves (40% owned in Yahoo!)

A.J. Minter has only five saves on the season, but he looks like he is in a position to get more over the next month or so. Incumbent Atlanta Braves closer Arodys Vizcaino has had some health problems this year, and he has gone to the disabled list twice now with shoulder issues. He is currently on the shelf and is seemingly not that close to a return.

Minter may not have the job for the rest of the reason (though, with the myriad of shoulder injuries to Vizcaino, he just might), but as long as he does, he should be a strong option. Minter has incredible stuff and has put together a pretty solid year. He has a 3.12 ERA and 2.49 FIP, both of which are above-average numbers. Overall, he is striking out fewer batters (26.4%) than you would like for a closer, but he has a strikeout rate over 30% since the start of June.

For the time being, Minter looks like he has the closing role locked up on a good squad. Even though it might not be a full-season thing, there is value in a player who can help you notch a few saves for a month or so.

Pedro Strop, Chicago Cubs (26% owned in Yahoo!)

Pedro Strop is widely available for those who need a very quick fix for saves. The longtime mainstay in the Chicago Cubs' bullpen has been getting plenty of save opportunities since their regular closer Brandon Morrow went down with a biceps injury.

Strop has been good since the Cubs acquired him midway through 2013, and this year has been no different. He is not the strikeout pitcher he once was (his 24.1% strikeout rate is by far the lowest of his Cubs career), but he is still able to record a 2.57 ERA and a 3.35 FIP.

There is some risk to picking up Strop, however. Morrow could be back fairly soon. On top of that, the Cubs have not committed to Strop being the guy sans Morrow. Despite all that, Strop has the second-most saves on the team (four) and has looked good doing it, so if you're in a deep league and need saves, Strop could be an option.

Honorable Mentions

The Mets recently traded Jeurys Familia, and someone has to take that job. Robert Gsellman, Anthony Swarzak, and Seth Lugo seem to be the three big guns in the bullpen (unless the Mets trade a starter and shuffle Lugo into that spot), so it stands to reason that one of them will end up taking the role. All three are widely available (Gsellman 29%, Lugo 13%, and Swarzak 3% owned) and are all dart throws to take the job. Lugo has been really good (2.34 ERA, 3.22 FIP), while Gsellman (4.03 ERA, 4.35 FIP) and Swarzak (6.75 ERA, 6.00 FIP) have struggled. One of them figures to take the gig, so you could do worse than rolling the dice on one of them if you have a roster spot to play with.

Lou Trivino has burst onto the scene for the Oakland Athletics and has been one of the biggest reasons why their bullpen has been so incredible. The rookie is striking out the world (30.1%) and is keeping the ball on the ground (50% ground-ball rate). He is not in line for many saves, though, as Blake Treinen has been excellent in that role. If you're in a deep league -- or a league that counts holds -- Trivino is an excellent source of holds and strikeouts.

The trade deadline always gives us new relievers to pick up for the stretch run, so stay up to date with the latest moves as a closer role could open up at any time.