Buy or Sell - Undervalued and Overvalued Players for Week 21

Pierre Camus takes a look at players who may be overvalued or undervalued in MLB week 21. These players could be buy or sell candidates for the 2018 fantasy baseball season.

Trade deadline passed? That doesn't mean you can't still buy and sell! Instead of trading assets with other owners, you can "buy" players that have been overlooked or recently discarded on the waiver wire. In this case, think of it as a short-term investment that comes at a low cost (you did save at least a couple bucks of FAAB for the final month, right?)

Rather than trade candidates, I'll focus on players that appear to be trending up or down, but could soon be headed in opposite directions. In other words, we'll find some undervalued and overvalued players for you to target in free agency, or the trade market if your league still allows.

As always, I will never advocate that you buy or sell a player if I wouldn't follow the same advice myself. Now, time to assess some fantasy values.

Undervalued Players - Week 21

Ian Kinsler (2B, BOS) 51% owned

Fresh off the DL, Kinsler has been somewhat forgotten despite moving to a major market team in the thick of a pennant race. Dustin Pedroia has been rehabbing all year and shouldn't be a concern at this point, so put your faith in Kinsler instead. He is off to a decent start in his first few games with Boston, but more importantly, he is batting fifth or sixth in the lineup, just behind MVP J.D. Martinez on some nights. He's only batting .241 on the season, but a .240 BABIP has room to grow. True, his hard hit rate is down from the last couple of seasons, but that and his other peripherals have seen even lower rates, but with greater success across major categories. A reinvigorated Kinsler could easily become a viable middle infield option in fantasy leagues the rest of the season.

Adalberto Mondesi (2B/SS, KC) 15% owned

You need steals, Mondesi is your new man. He's swiped 11 bags since the second half started with a decent .273 average. There is concern over an anemic 2.8% walk rate and little in his minor league past to suggest that will change, but when he does find his way on base, likely via single, he'll have free reign to run. Kansas City is eighth in SB attempts per game, but that rate is climbing in the second half. I've previously recommended Mallex Smith (and still do), but Mondesi is a bit more appealing since he slots in at the middle infield spot.

Harrison Bader (OF, STL) 23% owned

Despite earning an everyday role in the Cards' outfield and heading toward a 15/15 season, Bader is lightly owned across fantasy leagues. His plate discpline needs some improvement, but that's to be expected for a young player in his first full-time job. Bader is posting a 27.7% line drive rate - a positive sign that he can consistently make solid contact without relying on the home run ball to provide value. He never stole more than 15 bases in a minor-league season, mainly due to a low success rate, but if the team is going to let him run then he could continue to be a pleasant surprise in the area.

German Marquez (SP, COL) 38% owned

It's always a risky proposition trusting a Rockies pitcher, but Marquez is stringing together enough solid starts to convince me he can keep it up. He was a solid add early this season, but found trouble in June with a 6.75 ERA. Since then, he's settled down quite a bit, especially in terms of home runs allowed. Marquez has given up 20 HR on the year, but has limited the damage to three HR in the last 33.2 innings. He's figured out how to pitch in Coors clearly, as he ranks 20th among qualified starts in groundball rate at 47.5%. His best asset is that he presents high-strikeout upside, ranking 18th among qualified pitchers with a 9.69 K/9 already. There's always risk for a rough start if his gopheritis returns, but he's on a roll and is worth a shot given the potential to help in nearly every category.

Overvalued Players - Week 21

Ryan Zimmerman (1B, WAS) 60% owned

I'll keep this simple - I don't trust Zimmerman. He's been hot ever since returning from the DL, hitting .309 with five HR and 20 RBI in 21 games; the question is how long will it last? 2017 was an outlier in the sense that he hadn't played anything close to a full season since 2013. Once again, he's been back and forth to the disabled list and could break down at any time. The main thing to know about Zimmerman is that he does almost all his damage against left-handers, hitting .400 with a 9/9 BB/K and just as many homers in half as many at-bats than against right-handers. He bats just .188 with an 8/28 BB/K vs RHP. Zimmerman is a great daily play in the right matchups, but a risky player to rely on in weekly H2H leagues.

Ryan Braun (OF, MIL) 62% owned

The former MVP has shown flashes of his old self lately, swiping two bases in a game last week and jacking two homers in a game just days ago. Now injuries are rearing their ugly head again, as he is experiencing tightness in his ribcage. While not a serious injury, it's one that could affect his swing. For a 34-year-old that has already missed 34 games this year, it also doesn't bode well for his playing time. Between the Brewers' pre-trade deadline acquisitions and the emergence of Jesus Aguilar, Braun's bat isn't needed in lineup anymore; he can be benched in most leagues and dropped if need be.

Lance Lynn (SP, NYY) 59% owned

The honeymoon is over. Lynn pitched inspired ball after his move to the Yankees, allowing just one earned run in his first three starts. His last time out was a disaster, as he gave up five runs in four innings to the Blue Jays. This might seem like over-reaction to one bad start, but let's put things into perspective. Despite a solid 9.29 K/9 this season, Lynn is walking over five batters per nine and owns a 1.56 WHIP. His swinging strike rate is the highest it has ever been at 10.1%, but his first strike percentage has been dropping for four straight seasons, from 63.3% in 2013 down to 53.4% this year (he didn't pitch in 2016). He moves to a superior team, which should make for more win opportunities, but is facing AL East teams in the confines of Yankee Stadium half the time going to improve his ratios? I think not. Lynn's got the Marlins on tap next, which makes for a must-start in all formats, but it might be a good time to sell (or consider benching) shortly after.

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