Buy or Sell - Undervalued and Overvalued Players for Week 15

The trade market is about to go into a frenzy, both in reality and fantasy. The All-Star break offers a brief respite from the everday grind of the Major League schedule, but it is the perfect opportunity for fantasy owners to evaluate their rosters before making a final push for a championship run.

Scouting players who may be undervalued and re-assessing players who may be overvalued is a weekly exercise that you should constantly pursue as a dedicated fantasy baseball manager. Fortunately, I have you covered. Here are a few players who are good buy or sell candidates based on their current performance compared to ownership levels. This could mean scooping them off waivers if possible or actively seeking a trade to acquire or discard certain players in order to maximize value.

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 15

Robinson Chirinos (C, TEX) - 25% owned

By writing a weekly Statcast article on things like launch angle, it often leads to intriguing names to consider for this series as well. Chirinos is not only one of the league leaders in launch angle, but is sixth in HR and seventh in RBI among all catchers. It's hard to fathom that he's only owned in a quarter of leagues, as no-catcher leagues haven't caught on just yet. Unlike two seasons ago, it's unlikely the Rangers will try to bolster the position at the trade deadline since they are a last-place team. There are no enticing in-house prospects to develop either, so the 34-year-old vet should continue on pace for his first 20-homer season. The .210 average isn't enticing, but this is a catcher we're talking about.

Ryon Healy (1B/3B, SEA) - 39% owned

Healy never met a walk he liked, as his career 3.9% walk rate proves, but outside of points leagues that isn't a big problem. Healy has also seen his batting average dip from .305 as a rookie in Oakland to .271 to .248 this season. So what's to like? While his overall contact rate is down, he's got his contact inside the strike zone up to 90% and his Hard% up to 37.3%. His .267 BABIP should come up without sacrificing his power, making him a top-20 first baseman. He's outproducing higher-owned options like Eric Hosmer and Justin Smoak, while not far off players like Carlos Santana and Anthony Rizzo. I won't go so far as to say Healy is a must-start 1B in all leagues, but he's an ideal CI candidate.

Jorge Polanco (SS, MIN) - 14% owned

You may not have been on pins and needles waiting for Polanco to return from his 80-game banishment, but it's time to re-evaluate our expectations of him now that he's on the field again. Up until his suspension was announced, Polanco was the 17th shortstop selected in NFBC leagues, ahead of Andrelton Simmons, Yangervis Solarte, Brandon Crawford, and Gleyber Torres. There's good reason for that; in his first year as a regular, he produced a 13/13 season with 74 RBI. Polanco already looks to be in midseason form, starting out 6-for-18 with a pair of doubles. There's promise, but it's still unclear whether he can produce like he did in 2017. This version of the Twins is not nearly as good, with most of their big guns out of the lineup and uncertain to return soon. In deep redraft leagues you can take a chance as a bench stash, but in keeper leagues he should definitely be scooped up.

Danny Duffy (SP, KC) - 46% owned

After a promising 2016, Duffy didn't take the next step forward, he stepped back instead. While his final ERA was just .30 lower in 2017, his K-rate dropped four percent and his win total dropped by three. This year began as a waking nightmare for Duffy and his owners. In the first two months, Duffy posted a 5.71 ERA, 1.58 WHIP and gave up an uncharacteristic 14 HR in 64 innings. June was a different story as his numbers started to resemble career norms--he whiffed 29 batters in 30 IP while allowing a .214 AVG. His last start wasn't so hot, but at least he's getting his walk problem under control with just two free passes issued in each of the last two starts. His HR/FB is going down as well, with three balls leaving the park in his last five starts. He may not ever be the same pitcher as he was during his age-27 season, but even with a limited ceiling there could be value as long as you manage to avoid his occasional disastrous start (don't play him against Cleveland).

Overvalued Players - Week 15

Elvis Andrus (SS, TEX) - 82% owned

Blame it on the injury, but Andrus is not the same player. Even with a full complement of at-bats, it was unreasonable to expect 20 HR and 88 RBI. Last year stands out as a clear outlier in the power department, so his ADP was inflated from the start. Still, Andrus was supposed to deliver 25 steals with an average around .300. I'm not worried about his average since he's hitting the ball harder than ever, but going 0-for-1 in the stolen base department after 28 games is panic-inducing. The Rangers typically run a lot, but their SB attempts are down almost 20% from last season. If Andrus doesn't start running soon, he won't be worth starting in mixed leagues.

Mark Trumbo (OF, BAL) - 35% owned

Trumbo is gaining steam as a waiver wire pickup based on his latest power surge, but let's consider how much that's worth. If you own Trumbo, it's purely for home runs; he's never finished above .270 in any of his eight seasons. In terms of power, there are some paradoxes at play right now. Trumbo has a career-best 41.3% Hard% and a 21.3% HR/FB that approaches his 2016 mark of 24.8% when he jacked 47 HR. His 93.5 MPH exit velocity ranks 10th among all batters with at least 50 plate appearances. So, he's mashing the ball as one would expect. He is also posting the lowest fly ball and pull rates of his career. He is using all parts of the field like never before, evidenced below.

These are good things, no? No. Trumbo's power has never been in question. The frequency with which he makes contact and stays in the lineup regularly are the issues. Among other things, Trumbo owns a career-worst 14.7% Swinging Strike rate, is swinging at more pitches outside the zone, and is making less contact. The occasional hard hit ball will result in a homer, but he's never far away from a team-sinking slump. Speaking of teams sinking... the Orioles stink. Trumbo still has a year left on his current contract, but if he keeps mashing it could inspire a team to swing a deal for him if it helps them land Manny Machado. If Trumbo moves elsewhere, he won't be guaranteed everyday playing time anymore. Overall, his profile carries more risk than potential reward.

Luis Castillo (SP, CIN) - 58% owned

If you know what's what, you aren't starting Castillo any longer but I want to let it be known that I'm officially done with him for the rest of this season. There's got to be positive regression coming, right? That 66% strand rate, 19.4% HR/FB, .298 BABIP... Go ahead, keep waiting for it. Castillo's arm slot adjustment seems to not have been the problem after all. He has dropped 1.6 MPH on his fastball, 1.4 MPH on his sinker and over 2 MPH on his slider, resulting in fewer strikeouts. It's not as if you can count on wins to offset his ratios either. He might be better off getting more seasoning in the minors for the remainder of this lost season in Cincy, but even if that doesn't happen he is definitely better left off fantasy teams vying for a title.

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