Prospect of the Day: Theo Gillen and the TBR Prospect Group
PROSPECT OF THE DAY: THEO GILLEN
CF, TBR | as of 11/2/2026
Theo Gillen is the best prospect in a deep Rays system, and he is one spot away from the STS fantasy top 10. The 20-year-old center fielder sits at No. 11 with a projected 3.8 Peak WAR, and the player directly ahead of him is close enough to catch. What stands between him and that jump is one part of his projection: the power.
One of Six Rays in the Top 100
Tampa Bay places six prospects in the OOPSY Peak top 100, and Gillen leads the group: Gillen (center fielder, No. 11, 3.8 Peak WAR); Xavier Isaac (first baseman, No. 24, 2.3 Peak WAR); Taitn Gray (first baseman, No. 59, 1.4 Peak WAR); Nathan Flewelling (catcher, No. 75, 2.9 Peak WAR); Caden Bodine (catcher, No. 86, 3.0 Peak WAR); Austin Overn (center fielder, No. 98, 2.5 Peak WAR).
Clear of His Teammates
Gillen is first among those six whichever way you sort them, by STS fantasy ranking or by Peak WAR. Nobody in the system is close on either. The next-best Peak WAR belongs to catcher Caden Bodine at 3.0, and the next-best ranking belongs to Xavier Isaac at No. 24, 13 spots back.
An On-Base Engine With Speed
The on-base skills are what set Gillen apart. His projected .357 OBP ranks 6th among the 91 hitters in the OOPSY Peak top 100, and his 122 wRC+ ranks 13th. Speed is his best STS grade at 60, backed by a 55 hit and a 55 power. His 3.8 Peak WAR is the 17th-highest mark in the top 100, so his No. 11 ranking already sits a little ahead of his WAR.
What Moves Him Up
The next step is the top 10, and only one player stands in the way: Nationals pitcher Jarlin Susana at No. 10. Their Peak WAR projections are nearly even, 3.9 for Susana and 3.8 for Gillen. A small bump in Gillen’s projection could be enough to flip the order.
The Number to Watch
That bump would most likely come from home runs. His projected 19 homers rank 55th of the 91 top-100 hitters, just under the median of 21. A 55 power grade says the pop is there, but it hasn’t shown up in his projected line yet. If his stat lines start showing more power, that is the piece most likely to move OOPSY on him.
A Fair-Price Hold
Other formulated rankings place Gillen higher than OOPSY does: OOPSY’s ranking of him sits 12% below the Formulated Consensus, a blend of other projection-based rankings. Scout-based rankings, which we use as a rough stand-in for trade prices, have him inside the top 10, close to his No. 11 spot here. So his trade price looks about right. If you roster him, there’s no reason to sell, and if the power shows up, you’ll be glad you held.
Keep Digging
Every prospect’s STS fantasy ranking, Peak WAR and grades live on the OOPSY Peak page. STS members get the full rankings and player cards. Become a member. Back tomorrow with the next pick.
Data: OOPSY Peak as of 11/2/2026; Formulated Consensus as of 11/2/2026.