We're into the final quarter-season of fantasy baseball. Teams are starting to dig deep as they try to get a read on the future of their franchise. Fantasy owners will need to remain nimble. Whether you're a contender or a rebuilder, snagging quality players off the waiver wire is an important part of August and September.

Last week, Francisco Mejia appeared in this column for the second time this season. Generally, I try to avoid repeats unless some bit of news demands attention. In Mejia's case, it was a long hitting streak. It ended on Sunday night at 50 games. The Indians catching prospect did draw a walk in the game so his on base streak continues at 51 games.

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Dynasty Advice for Week 20

Vladimir Guerrero Jr. - Toronto Blue Jays

Yep, that Vladimir Guerrero. One of the highest profile players to come out of the Dominican Republic in recent years, Guerrero is tearing through rookie league as a 17-year-old. He's batting .275/.361/.472 with seven home runs, 15 steals, and nearly as many walks as strikeouts - all while transitioning to third base.

I've been sitting on a Guerrero write-up for awhile. In my deepest dynasty league, I drafted him while he was still a 15-year-old. He's anywhere from three years to half a decade away from major league action. In that time, his profile will probably change considerably.

He already has a mature body which is easy to see in this video of him sending a ball a long way with a bad swing. The speed plays fine on the bases in rookie ball, but he'll be hard pressed to take bags in the upper minors and majors. Plan for him to be a power-first prospect with 30 or more home run potential. The club currently has him learning third base, and it's too soon to say whether he can stick there. Most likely, he'll wind up in the corner outfield or at first base.

This Guerrero doesn't share his father's ability to put the barrel on pitches anywhere within five feet of the plate. Expect Junior to be a classic power hitter with typical walk and strikeout rates.

Teoscar Hernandez - Houston Astros 

While Carlos Gomez stole the headlines out of Houston this week, the club quietly called up a meaningful prospect in Teoscar Hernandez. The outfielder already has his first major league home run after belting 10 in 481 plate appearances split between Double- and Triple-A. Hernandez also stole 34 bases, although his steal rate dropped dramatically upon reaching Triple-A.

Prior to this season, Hernandez struggled with high swinging strike rates which prevented him from actualizing his talent. He seemingly adjusted in the minors this year. Although 13 major league plate appearances are far too few to draw any conclusions, it's not encouraging to see his whiff rate spike to a career worst. Keep an eye on it.

Since Jake Marisnick has been terrible at the plate this season and only league average defensively, Hernandez has an opportunity to snatch the starting center fielder job in Houston. The best case scenario includes five home runs and 10 steals over the rest of the season. We're more likely to get two to three blasts and five swipes. Barring a terrific September and October, the 23-year-old is unlikely retain the starting job beyond this winter.

The Astros have every reason to purchase an external solution while their club remains competitive. Hernandez's profile fits in that 3.5 outfielder mold - he's good enough to start (at least based on his profile), but you'd rather he be your top bench guy. As such, his dynasty value is difficult to gauge - there are a lot of "if's" in play.

Rapid Fire

Bobby Bradley - Cleveland Indians

Bobby Bradley Boom. The first base prospect has homered in three consecutive games, bringing his season total to 25 taters in 489 High-A plate appearances. Bradley is one of several prospects in the minors with big home run potential and questionable contact skills. When the profile comes together, you wind up with players like Chris Davis and, uh, Khris Davis. Bradley is only 20 years old, so he still has a few years to make more contact.

Jahmai Jones - Los Angeles Angels

Jones is a fine prospect, but he'd rank in the latter half of most team top 10 lists. He's arguably the best the Angels have - 2016 first-round pick Matt Thaiss is also a candidate for top Angels prospect. Having increased visibility is usually good for a career. There's real value to being the top prospect in your system, even if there's relatively little competition for the title. Jones is a speed-first guy with decent discipline and contact skills. He recently turned 19 and should debut in Low-A next season.

Yoan Moncada - Boston Red Sox

The Red Sox are signalling that they believe Moncada is nearly ready for a call-up. When a prospect's position is blocked in the majors - as Moncada is blocked by Dustin Pedroia - the last thing a team will do is train them at a new spot. Moncada made his debut at third base on Sunday, and the team has announced he'll play there in the Arizona Fall League too.

For those hoping to see him this season, prepare yourself to wait until late-April 2017. Boston doesn't need to put him on the 40-man roster now, and they have plenty of names to protect. The Red Sox will probably give Pablo Sandoval and Travis Shaw one more "chance" to take the third base job next spring. It'll be pure coincidence that the Sox will also gain a full year of club control over Moncada by waiting a few weeks into the season.

T.J. Rivera - New York Mets

Rivera, a 27-year-old utility man, may have a chance to carve out a role for himself with the Mets. The righty has an aggressive, line drive oriented approach at the plate which helped him produce high BABIPs in the minors. It remains to be seen if that skill will translate to the majors. He showed career best power at Triple-A with 11 home runs in 406 plate appearances. His profile doesn't check any of the boxes scouts love, but it hasn't stopped him from conquering every minor league assignment.

Josh Lowe - Tampa Bay Rays

Lowe, 18, was the Rays top draft pick this past June. He earned his first promotion last week to the GCL (a higher level of rookie ball). He may have a chance to open the 2017 as one of the youngest players in Low-A. Lowe has performed well through his first 142 plate appearances with five home runs, a couple walks, and a solid walk rate. He's struck out more than I'd like to see, but it's too early to worry about that lone blip in his profile.

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