10 Fantasy Baseball Players to Buy and Sell for Week 19

With Week 18 in the books and the playoffs on the horizon, it is officially decision-making time regarding your fantasy baseball team.

Maybe your squad has been plagued by injuries, and it is time to cut bait on guys you would have preferred to hold on to because you're in win-now mode. Maybe you have 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 right now, you should always be looking to take advantage of market inefficiencies on players.

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 on. 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 Jose Quintana

After watching Jose Quintana hurl three straight quality starts in a Chicago Cubs uniform, many were ready to jump back on the bandwagon. However, following a six-run implosion in his last start, the buy-low window might be opening once again.

Over the past 30 days, only six other pitchers have a better xFIP than Quintana's 2.91 mark and he has the league's third-best strikeout rate (34.8%) among starting pitchers during that stretch. Quintana's sub-3.00 xFIP since joining the National League is encouraging enough to justify making a buy-low offer on him, who might still be able to be had for cheap, based on his 4.42 ERA.

Buy Rougned Odor

Rougned Odor just cannot seem to find any luck this season -- he has found himself in the bottom-10 in BABIP all season, currently ranking third-worst with a .230 mark. It has been even worse as of late, as Odor has just a .205 BABIP over the past 30 days despite a 42% hard-hit rate.

Odor has shown flashes of dominance, most recently belting seven home runs in a nine-game stretch to close out the month of July.

He might not end with a batting average anywhere near last season (.271), but Odor should definitely improve on his .217 mark over the remaining months of the season. He already boasts elite power for a middle infielder, and with some better luck on balls in play, Odor could be a true difference maker down the stretch.

Hold Alex Bregman

There have been few hitters hotter than Alex Bregman since the All-Star Break, who has a .450 wOBA and .689 slugging percentage during that time. After watching him struggle mightily to begin the season, many owners will take this opportunity to try to buy low based on his weak season-long numbers. It might be tempting to sell Bregman while he's hot, but a deeper look suggests this might not just be a blip on the radar.

As the table displays, Bregman has improved across the board, making harder contact and making it more often while walking more and cutting down tremendously on his strikeouts. He is a young player and could certainly get cold again, but the underlying numbers suggest this is a step forward and not just a hot streak.

Add Rafael Devers

Rafael Devers continues to mash since being called to the majors, and now boasts a .349 batting average and .605 slugging percentage in 11 games, which is backed by a 40.6% hard-hit rate and 80.3% contact rate.

He's somehow still available in over 40% of ESPN leagues despite four straight games hitting out of the five-hole for one of the league's most dangerous lineups. If he is still available in your league, be sure to put a waiver claim in on the talented rookie.

Buy Jimmy Nelson

It seems bizarre to call a pitcher with a 3.24 ERA (2.82 since the start of July) a buy-low candidate, but that is exactly what Jimmy Nelson is. How? Because, while his base-line numbers are awesome, they don't capture just how effective he has been, especially lately. Also, Nelson had a career 4.38 ERA entering this season, so many fantasy owners still are reluctant to buy into him as a fantasy ace despite his consistent dominance.

Nelson ranks sixth among qualified starting pitchers in xFIP (3.10) while also ranking inside the top-10 in BABIP against (.327), making him the only pitcher to do both. Somehow, he's pitched through his bad luck on balls in play to post one of the league's strongest ERAs.

The hurler has been even better over the past 30 days, ranking fourth with a 2.58 xFIP while also finding himself inside the top-10 in strikeout rate (30.7%) during that time. Nelson isn't going to be cheap, but he likely won't be as expensive as his numbers indicate that he should be.

Sell J.C. Ramirez

When heading into the fantasy playoffs, hot pitchers are valuable commodities. While J.C. Ramirez's season-long numbers are nothing to marvel at, he certainly has been hot recently. He is coming off an eight-inning shutout performance, which has his ERA down to 1.93 over his past five starts.

It's been fun to ride Ramirez's hot streak, but it isn't likely to last for much longer. Over the past 30 days, no pitcher has seen a larger discrepancy between their ERA and SIERA than Ramirez, who has the league's third-worst SIERA (5.47). Despite his sub-2.00 ERA, he has just 20 strikeouts to 17 walks during that span.

If you can get any value back for Ramirez based on his recent success, do so now before his peripherals catch up to him.

Add/Buy Mitch Moreland

After back-to-back seasons of 20-plus homers, Mitch Moreland is well on his way towards another thanks to what would be a career-high 42.6% hard-hit rate. Over the past 30 days, his 44.6% hard-hit rate is the ninth-highest in the league, but few have noticed due to his .204 BABIP during that time -- sixth-lowest in the majors.

Another encouraging sign for Moreland is his expected wOBA (xwOBA) of .377, which is 56 points above his actual wOBA (.321), gives him the second-largest discrepancy between the two. There should certainly be some positive regression headed his way soon.

Sell Lance Lynn

Perhaps no pitcher has outperformed their peripherals more than Lance Lynn, who has a 3.12 ERA but a 4.59 xFIP that screams regression. It's been even more ridiculous recently, as Lynn has danced around a 4.78 xFIP to put up a sparkling 1.21 ERA over his past six starts. He has an ugly eight-to-seven walk-to-strikeout ratio over his past two starts and hasn't struck out more than more than six batters in a start since June.

No pitcher has seen their opponents post a lower BABIP (.221) than Lynn, who clearly has been the beneficiary of some extraordinary luck.

Lynn might continue outperforming his peripherals for a few more starts, but nobody can completely outrun regression -- just ask Ervin Santana or Jason Vargas, who profiled similarly over the first half of the season, but both have an ERA well above 4.00 over their past 10 starts.

Add Amed Rosario

The New York Mets finally gave top-prospect Amed Rosario the call last week. It has been a bit of a slow start, it is encouraging that he has started every game since arriving. Once he acclimates himself to the majors, it wouldn't be surprising to see him moved up from the seventh spot in the order, either.

Rosario projects as someone who can be a difference maker in fantasy and should be given regular at-bats down the stretch. He is well worth throwing a dart on and is still available in over 60% of ESPN leagues.

Buy Masahiro Tanaka

Masahiro Tanaka built on his 14-strikeout performance with another quality start his last time out, striking out seven over six innings while allowing just one earned run. He now has the league's third-best xFIP (2.51) over the past 30 days, as well as the 12th-best on the season (3.50).

Those peripherals are excellent, but they come nowhere near matching his 4.93 ERA, which should allow you to make buy-low offers on Tanaka, even though he has piled up 21 strikeouts over his past two starts.