A previously slow offseason has now picked up in large part to the trade market, so we're taking a look at the top MLB prospects who have moved in trades this winter.
Two teams, the Tampa Bay Rays with six players and Pittsburgh Pirates with nine, make up well over half of our 25-prospect list.
Tampa Bay is perpetually flipping more established, higher-paid players for prospects that are accruing value, with an efficiency that's been the envy of the league. Meanwhile, Pittsburgh in a full tear-down fire sale where they're mostly targeting quantity and quality from the lower minors, usually with a good bit of variance/upside while trading any player with an established big league track record.
Here are our the top 25 prospects who have changed teams this winter along with their future value (FV) on our 20-80 scale. Note that the Nolan Arenado trade is not included because no prospects included have been made official yet.

1. Luis Patino, RHP, Rays, 60 FV (from SD in Blake Snell trade)
Patino may have the best raw stuff among prospect-eligible arms right now, and his short MLB debut in relief during the 2020 season doesn't change his long-term outlook.
He's a smaller righty with an electric arm and is a plus athlete, so average control should be fine to let his stuff play at the front of a rotation.
There's a lot of industry chatter that the Rays excellent pitcher development could make him their next breakout star like Tyler Glasnow, even though the two are opposites physically.

2. Dane Dunning, RHP, Rangers, 50 FV (from CHW in Lance Lynn trade)
Dunning has had a rocky road of late, with Tommy John surgery and some plateauing in his prospect value, but had a strong MLB debut in 2020. He's a league-average No. 4 starter right now and has a shot to ride his above-average offspeed stuff and command to even a bit better than that.

3. Blake Hunt, C, Rays, 45+ FV (from SD in Blake Snell trade)
Hunt was one of the half-dozen biggest gainers among prospects from a minor league season behind closed doors. The Rays pro scouting group is notorious for their exhaustive coverage, so scouting looks during instructional league play moved him to the top of the target list in their Snell deal.
With another half-season of seeing how his new level plays in the minors, Hunt will likely find his way onto the top 100. In short, he was a guy with the tools for average hit and power grades as a strong defender, and he's actualized that potential in all phases in the last year, particularly at the plate. He could be the long-term catching answer for the Rays as soon as 2022.

4. Hudson Head, CF, Pirates, 45+ FV (from SD in Jose Musgrove trade)
5. Miguel Yajure, RHP, Pirates, 45+ FV (from NYY for Jameson Taillon)
The two best prospects received by the Pirates in their two moves dealing away major league starters are both just on the outside of the top 100 -- but could get on there with a strong first half of 2021.
Head was a late-rising dual-sport athlete out of a Texas high school who got a first-round bonus in the third round of the 2019 draft. A strong half-season in low-A where his tools start matching the performance will vault him onto the top 100, as it has for a number of young bats in the 2018 prep hitter class.
Yajure had a velocity spike in 2019 that led to a short look in the majors during the shortened 2020 season. There's mid-rotation upside if everything comes together, but Yajure settling in as a reliable No. 4 starter is more likely.

6. Cole Wilcox, RHP, Rays, 45 FV (from SD in Blake Snell trade)
Wilcox is a strong third piece from the Snell trade who got first-round money in the third round out of Georgia last summer -- after turning down first-round money out of high school two summers before that. He has flashed three plus pitches and starter traits, but never shows them all in the same outing, with everything except the velocity coming and going from game to game

7. Heriberto Hernandez, LF, Rays, 45 FV (from TEX in Nate Lowe trade)
There's some chance Hernandez could catch, but it is more likely he ends up as a first base/left field type. He is still in the lower minors but he has the potential to produce as a plus hit/power combo from a squattier frame, drawing parallels to a young Kyle Schwarber.

8. Yeison Santana, SS, Cubs, 45 FV (from SD in Yu Darvish trade)
9. Reggie Preciado, SS, Cubs, 45 FV (from SD in Yu Darvish trade)
Santana and Preciado were the best of the four lower-level prospects the Cubs targeted in the Darvish deal.
Santana has a compact frame and precocious feel at the plate, with a pretty swing and bat speed that has been steadily growing since he signed as an amateur, as well as a solid shortstop fit.
Preciado signed in the 2019 July 2 class, so has been seen only in two instructional leagues and hasn't played an official pro game yet. He's a lanky switch-hitting infielder with body control and bat speed. The elements are here -- like with another dozen or so players in the low minors -- to dream of a Corey Seager-like upside, but with precious little proof he can reach it so far.

10. Maikol Escotto, SS, Pirates, 40+ FV (from NYY in Jameson Taillon trade )
Escotto was the best of the three lower-level prospects the Pirates received for Taillon. He still has a limited track record, but got on the radar with a strong 2019 DSL season (the Dominican Summer League is now scouted by more than a handful of clubs) and instructional league. He's a contact-first infielder who probably moves to second or third and has sneaky pop, akin to a Martin Prado type.
More top traded prospects:
11. Canaan Smith-Njigba, LF, Pirates, 40+ FV (from NYY in Jameson Taillon trade)
12. Roansy Contreras, RHP, Pirates, 40+ FV from NYY in Jameson Taillon trade)
13. Josh Wolf, RHP, Indians, 40+ FV (from NYM in Francisco Lindor trade)
14. Osleivis Basabe, SS, Rays, 40+ FV (from TEX in Nate Lowe trade)
15. Eddy Yean, RHP, Pirates, 40+ FV (from WSH in Josh Bell trade)
16. Wil Crowe, RHP, Pirates, 40+ FV (from WSH in Josh Bell trade)
17. Endy Rodriguez, C, Pirates, 40 FV (from NYM in Jose Musgrove trade)
18. Ismael Mena, CF, Cubs, 40 FV (from SD in Yu Darvish trade)
19. Owen Caissie, RF, Cubs, 40 FV (from SD in Yu Darvish trade)
20. Isaiah Greene, CF, Indians, 40 FV (from NYM in Francisco Lindor trade)
21. Frank German, RHP, Red Sox, 40 FV (from NYY with Adam Ottavino)
22. Jameson Hannah, CF, Rockies, 40 FV (from CIN in Jeff Hoffman trade)
23. David Bednar, RHP, Pirates, 40 FV (from SD in Jose Musgrove trade)
24. Garrett Stallings, RHP, Orioles, 40 FV (from LAA in Jose Iglesias trade)
25. Alexander Ovalles, 1B, Rays, 35+ FV (from TEX in Nate Lowe trade)