As we enter week 12, we're nearing the midpoint of the MLB season. By now, most owners are reaching decisions regarding their teams.

Maybe your team has been plagued by injuries, and it's time to cut bait on guys you would have preferred to hold on to because you're in win-now mode. Perhaps you find yourself with a comfortable lead in the standings and can afford to take a chance on some buy-low players in hopes of a bounce back heading into the later stages of the season.

Regardless of where your team sits, you should always be looking to take advantage of market inefficiencies.

Perhaps a slow start is just a product of bad luck and a small sample size. Maybe the reason you're in first place is due to the stellar but possibly unsustainable play of some players you can sell high. If you're not sure whether you should hold or fold on a player, don't sweat it. That's why we're here.

The following 10 players have seen a perceived change in their fantasy stock, and we'll attempt to decipher which warrant taking action.

Buy Sonny Gray

After watching Sonny Gray maintain a sparkling 2.64 ERA through his first three professional seasons, last year's injury riddled campaign in which he posted a 5.69 ERA was a colossal disappointment. He opened this year injured and has carried a 4.44 ERA through his first nine starts, so his recency bias has Gray's value at an almost all-time low.

While his 4.44 ERA might not be encouraging, Gray's peripherals suggest he's pitching at a level much closer to his first three years -- perhaps even better. His 3.27 xFIP is the lowest he's posted since his rookie campaign, as is his 9.06 strikeouts-per-nine-innings (K/9).

He's been dealing over the past 30 days, posting the third-lowest xFIP in the league. Despite his 2.56 xFIP and 10.80 K/9 during that stretch, Gray has still put up just a 4.80 ERA in his past five starts. What gives? Well, his .390 BABIP during that span is the fourth-highest in the league, while his 57.7% strand-rate is the fifth-lowest mark. For the season, his .329 BABIP and 60.9% are both career-worsts, topping even last season's disaster.

Gray has also posted a career-best 75.4% contact rate against, as well as a 11.3% swinging-strike-rate. The only thing that appears to be holding him back from positing some of the strongest numbers of his career is his bad luck on balls in play. Buy low on him now, and hope that the underlying numbers correct themselves soon.

Sell Michael Fulmer

On the other end of the spectrum, when it comes to luck and recency bias, we find Michael Fulmer, who has built on last season's solid showing (3.06 ERA) with a 3.45 ERA through his first 13 starts of 2017. However, his K/9 has dropped from an unspectacular 7.47 mark in 2016 to a dreadful 6.59 mark this season, while his xFIP has dipped from 3.95 to 4.14.

His contact rate is up to 80.4% on the year, and only 16 pitchers have allowed contact at a higher rate than Fulmer over the past 30 days (83.3%). Fulmer's luck has appeared to be catching up with him in the month of June, though, as he has more runs allowed (13) than strikeouts (nine) in his 18 innings pitched.

At this point in his career, it is pretty clear that Fulmer is not going to offer much in the stirkeout category, so his value is largely tied to his ability to keep his ERA down. He's been able to out-pitch his peripherals thus far, but his recent cold streak is troubling enough that it might be time to listen to trade offers. If you can get someone to buy-high on the hypothetical upside of a 24-year-old pitcher with a career 3.20 ERA, do so while you still can.

Buy Kyle Seager

Kyle Seager can be an infuriating player to own through the first few months of the season, but generally turns it on as we get deeper into the season. This year has been no different, as he posted a .242 batting average and .369 slugging percentage through May 20, but has bounced back with a .289 batting average and .465 slugging percentage since.

After struggling early on, Seager has his hard-hit rate up to 38.9%, which would mark a career-high and the third-consecutive season of improvement in that category. He also has a xwOBA, or expected wOBA, of .369, as opposed to his actual wOBA of .324, which gives him the 10th-largest discrepancy between the two, and is a clear indicator of bad luck.

The window to make buy-low offers on Seager might be quickly closing as he begins to heat up at the dish, so be sure to get in touch with his owner while you still can. When he's locked in, he can be a difference maker in fantasy.

Add Jacob Faria

Few of the mid-season call-ups have shined brighter than rookie Jacob Faria, who has been flat out dominant in his three big league starts. The talented 23-year-old righty has won all three outings, while piling up 22 strikeouts in 19.2 innings, and compiling a 1.37 ERA and 0.97 WHIP.

Perhaps even more impressive is the list of opponents against whom he's done it, as all three rank inside the top-10 in wOBA over the past month.

Faria's 2.77 xFIP backs up the fact that he's been pitching at an elite level, and his 74.8% contact rate against and 12.4% swinging-strike-rate suggest his impressive strikeout rate thus far could be legit. Even if he isn't quite the ace he looks like right now, Faria is worth a speculative add, and is still available in over 50% of ESPN leagues.

Sell Xander Bogaerts

Xander Bogaerts has been one of the most useful middle infield options available in fantasy this season, as he has paired a .318 batting average with 43 runs and eight stolen bases. However, the underlying numbers suggest there's some regression headed his way.

Among 347 qualified batters, only two have a larger discrepancy between their xwOBA and actual wOBA than Bogaerts, who ranks 26th among players with shortstop eligibility in expected wOBA.

One big concern for Bogaerts is that, if his wOBA were to regress, he hasn't shown enough power to sustain value. While some may point towards last season's 21 homers as reason for encouragement, it's important to remember that Bogaerts never hit more than 12 homers in a season prior to last year. His hard-hit rate has hovered around the 30% mark for three consecutive seasons, and he has just a 32.6% career fly-ball rate, a number which is down to 28.8% this season. These numbers are not indicative of a power outburst, and it is becoming more and more apparent that his 2016 contribution in the home run department was an outlier.

Don't take this the wrong way -- Bogaerts is a quality player in an explosive lineup. However, if you can find an owner in your league that values him near or in the elite tier of fantasy shortstops, sell-high.

Add/Buy Logan Morrison

Another week gone by, and Logan Morrison is still crushing baseballs with no remorse. He has the league's 17th-ranked hard-hit rate, as well as the 28th-ranked xwOBA. He's paired his 42.8% hard-hit rate with a 47.6% fly-ball rate, both of which are career-bests and make him one of just six other players with a hard-hit rate above 40% and fly-ball rate above 45%. When you take a look at his underlying numbers and not just his name, it makes his 47-homer pace seem a lot more legitimate.

While he probably won't reach that mark, it is encouraging that everything about his batter profile points towards the power being legit. In fact, one could argue that Morrison has been a victim of bad luck this season. His .241 BABIP is the 11th-lowest in the league and suggests that there is room for improvement in his .245 batting average.

He is still available in over 50% of ESPN leagues, which is somewhat mind-boggling given how well he has played. If he's still available in your league, put in a claim for him now. If not, check with his owner to see if he can still be had for cheap.

Sell Dylan Bundy

There have been just 15 starting pitchers with a worse xFIP than Dylan Bundy's 5.13 mark this season. Among them, only two have an ERA below 4.00 and none have an ERA lower than Bundy's. The former prospect has benefited from extraordinary good luck (.261 BABIP and 81.8% strand rate), which has allowed him to mask his otherwise uninspiring peripherals with a 3.29 ERA.

Bundy has posted a pedestrian 6.47 K/9 this season, while his strikeout-to-walk-rate of 10.5% is in the bottom-third of the league.

He's also allowed an alarmingly high 46.7% fly-ball rate this season, the fourth-highest mark among qualified starting pitchers. While his 10% home run-to-fly-ball-rate has kept that from being a major issue so far, a pitcher who allows contact on nearly 80% of his pitches while nearly 50% of contact surrendered is of the fly ball variety is almost always the recipe for someone who's susceptible to the long ball.

It is only a matter of time until Bundy's xFIP and ERA begin to align more closely, which is troubling news for owners of the exciting young hurler. If you happen to find yourself in that category, it is worth exploring trade options, using his youth and 3.29 ERA as selling points.

Buy Marco Estrada

After back to back seasons of outperforming his peripherals, Marco Estrada has decided to continue to torment analytics-driven minds in 2017, but this time as the recipient of bad luck. Estrada's 3.88 xFIP this season is the best mark he has posted since 2013, while his 4.54 ERA is the worst he has posted in a season he has pitched at least 75 innings.

While it seems like simplifying things, finding an explanation might be as easy as looking at his BABIP. After back to back years of posting a sub-.250 BABIP, Estrada's BABIP has climbed to .336 this season, which is the 10th-highest in the league.

If not for extremely bad luck on balls put in play, Estrada might be one of the league's most dangerous pitchers. He has paired the league's 14th-ranked SIERA (3.63) with a career-best 10.18 K/9. Over the past 30 days, only four pitchers have a better strikeout-to-walk-rate than Estrada's 6.8 mark.

After years of fantasy players not believing in Estrada's results, the 33-year-old might be very had following his slow start. Send his owner some buy-low offers, because the underlying numbers suggest that positive regression is headed his way.

Sell Avisail Garcia

Avisail Garcia has ridden a ridiculous .404 BABIP (the third-highest mark in the league) to a .332 batting average through 66 games for the Chicago White Sox, which is 49 points above his career-high mark. While his career .333 BABIP suggests that Garcia might just have the skill set to be a high BABIP player, the rest of his hitter profile suggests that there is almost no way his batting average is sustainable.

While Garcia's free-swinging ways can certainly lead to hot streaks, it is not the correct approach for maintaining a batting average near .300 over the course of a full season. Among qualified batters this season, only two have swung at pitches outside the zone more frequently than Garcia (42.6%), who also has the league's fifth-highest swinging-strike rate (16.4%) and 25th-lowest contact rate (72.5%). In fact, only seven other players have combined a contact rate of 75% or lower with a outside-swing-rate of 40% or higher over the past two seasons. As you can see below, they weren't able to maintain a batting average anywhere near Garcia's .332 mark.

Garcia's batting average is going to fall. The real question is, will it be far enough that you can't stomach his strikeouts (22.2%) and lack of walks (4.1%)?

This isn't to say that Garcia won't still be a usable fantasy asset over the course of the season, but rather that he won't continue to be the elite option he has been thus far. If someone in your league is willing to buy-high on his early-season breakout, take advantage.

Buy Jeff Samardzija

Ah, Jeff Samardzija, possibly the most frustrating example of a pitcher's peripherals and base numbers not lining up. The 6'5" righty is joined by the likes of Chris Sale, Lance McCullers, Dallas Keuchel, and Clayton Kershaw in the top-five in xFIP this season, yet his ERA (4.81) stands two whole runs above each of them.

After posting a 2.76 ERA over a strong five-start stretch, Samardzija was bombed to the tune of 11 hits and eight runs at Coors Field in his last outing. His next start again comes on the road, which marks nine of his first 15 starts away from his home field, where he has a more respectable 4.34 ERA.

Even considering the fact that he's had to pitch an unusual amount of starts on the road -- including two at Coors -- Samardzija's main issue has been bad luck, which is evidenced by his .333 BABIP and 64.9% strand rate.

If Samardzija's peripherals do begin to balance out, he could end up being one of the league's most dominant pitchers down the stretch, as evidenced by his top-five xFIP and his third-ranked strikeout-to-walk rate (24.1%).