Buy, Sell or Hold: Stuck in the Middle Infield With You

Like the stock market, fantasy baseball is about buying low and selling high. There's value to be had by those that stay a step or two in front of the next trend. This Buy, Sell or Hold will look at newsworthy middle infielders -- some of the scarcest positions to find fantasy contributors.

Buy

2B/SS Aledmys Diaz, St. Louis Cardinals

It's hard to project what Diaz's ceiling is because his rise has been so quick. He had a cup of coffee in AA and a shot of espresso in AAA last season. It took an injury to push him all the way to the show.

What we know is this: he hasn't struck out much (or walked) because he has been knocking the cover off the ball to the tune of a .400 batting average. That's not sustainable, as his matching .400 BABIP backs up, but if he can hit above .280 and provide some pop at the bottom of the order, he'll be a mainstay for a Cardinals team that needs a SS.

It's possible that pitchers find the holes in his swing within a month and Diaz is sent back to AAA for more fine-tuning. Until that point, he brings RBI and homer potential. Eligibility at both infield positions will surely help in daily lineup leagues.

SS Marcus Semien, Oakland Athletics

Semien still has the physical gifts that have hung with him throughout the minors and parts of four seasons in the majors. Last season, he hit 15 HRs and stole 11 bases; only three other shortstop-eligible players -- Manny Machado, Carlos Correa and Ian Desmond -- totaled at least 15 and 10.

The reason why he is vastly under-owned in standard leagues is because he is hitting just .208. Unlike Diaz, Semien has been very unlucky. His BABIP sits at .194, a result of his line drive rate falling to 7.5 per cent, the 7th-lowest mark in the majors. When he rebounds to his career average of 21.7 per cent, both his batting average and on-base percentage will increase substantially, as will his contributions in runs and RBIs.

It's easy to forget that Semien is still only 25 years old. The Athletics don't look like contenders this year, despite a 10-7 start, so Semien may begin to see higher spots in the order. If he's available, pick him up; if you've already got him, hold onto him.

Sell

SS/3B Eduardo Nunez, Minnesota Twins

The Twins have located Nunez at the intersection of optimism and desperation, hoping that he can serve as a stop-gap leadoff man until someone (anyone?) plays themselves back into the role.

Nunez is ill-suited to lead off. He sports a career 5.4 per cent walk-rate that has fallen to 2.4 per cent this season. The three steals in 13 games so far is incongruous with how he has been used since joining the Twins organization. His current hot streak (.405 batting average, .966 OPS) is tied to massive jumps in everything from line drive rate to hard-contact rate, none of which should prove sustainable over a larger sample size.

Nonetheless, his positional versatility in fantasy baseball mixed with his apparent (but misleading) maturation as a hitter will lead to someone overpaying for him in a trade. If you are the owner that has enjoyed his productivity to date, try to trade him fast. Regression is inevitable.

SS Jordy Mercer, Pittsburgh Pirates

Mercer has had a great couple of days at the plate, leading off against the first two starting left-handed pitchers the Pirates have faced this year. In those two outings, Mercer had six hits and a walk in nine plate appearances, racking up two runs, two RBIs, a homer and a double. He also added his first steal of the season.

As a result, his ownership levels saw a slight bump. The reality is that 1B John Jaso will continue to lead off against right-handed pitchers, and playing time in the infield is due to tighten up with the return of 3B/SS Jung-Ho Kang. Mercer's owners aren't going to find any takers for his talents, so at this point, his use should be restricted to daily fantasy.

Hold

2B/SS/OF Kike Hernandez, Los Angeles Dodgers

Los Angeles' outfield, as is the case currently, has dealt with injuries on a consistent basis for years, and Hernandez has the versatility to fill in at multiple positions. This season, he has already made appearances at second base, third base and all three outfield positions.

The Dodgers are reluctant to play Hernandez every day but have had him lead off every time they've faced a left-handed pitcher. He is a career .392 hitter against LHPs but his .242 BA against righties has held him back from a full-time role. If the situation changes and Hernandez has an opportunity to hit against RHPs on a consistent basis, he will be a contributor in average, OBP, RBI and homers.