When scouting amateur players, scouts are always on the lookout for raw athletes who may not have a lot of baseball experience but who can be (theoretically) taught how to play the game and molded into impact players. Much of the time the raw tools guys do not pan out as hoped, but occasionally someone takes that step from athlete to baseball player.
From the 2016 Baseball Prospect Book:
Trayce Thompson, OF, Los Angeles Dodgers
Bats: R Throws: R HT: 6-3 WT: 215 DOB: March 15, 1991
2010: Grade C; 2011: Grade C; 2012: Grade C+; 2013: Grade B-; 2014: Grade C+
2015: Grade C+
I write the same thing about this guy every year, with good reason: his strengths and weaknesses don’t seem to change. He’s an excellent athlete with power and speed. He can kill a mistake pitch. And he is a first-rate defensive outfielder. All still true. His problems also remain the same: his swing mechanics are troublesome, he strikes out a lot, and he has a hard time keeping his batting average anywhere close to respectability.
Trayce Thompson had the best year of his professional life in 2015, making adjustments to his swing and cutting way back on the strikeouts that plagued him. As a result he had a good year in Triple-A then hit very, very well against big league pitching in 44 games with the White Sox, much better than could have been expected based on his track record. The tools for him to do this have always been there, but the refinement wasn’t. The question: was this a permanent change, or will he slip back into old patterns? The White Sox traded him to the Dodgers in the Todd Frazier deal, perhaps thinking that they needed to sell this stock when it was high. Thompson has lost some running speed over the last couple of years but his usable power has improved. We should not expect him to hit .295 over a full season but it looks more likely that now that he can hit .250-.260 with enough power and defense to be worthwhile. Grade B-.
Thompson led all Dodgers players with 75 at-bats this spring so the coaching staff got a good look at him. He hit just .213/.244/.400 with a poor 2/16 BB/K ratio, but he also knocked three homers and earned a spot on the Dodgers bench. He's appeared in six of seven Dodgers regular season games, going 4-for-10 with a pair of doubles, three RBI, a walk, and three strikeouts.
Thompson hit .295/.363/.533 in his 44-game trial with the White Sox last year and is now a career .303/.370/.538 hitter with five homers, 14 walks, and 29 strikeouts in 132 at-bats. That sounds great and it is; he's played well defensively too and his career fWAR stands at 1.6 in 146 plate appearances.
Put another way, that's 6.5 fWAR in 600 plate appearance notation, which would make him one of the best players in baseball if he continued to play like this.
I'm of two minds on this. On the one hand, I've seen Thompson flail helplessly at breaking stuff outside the zone or get tied up on inside fastballs too often in the minors to completely buy this. He certainly had issues with contact in spring training. On the other hand, his swing IS better than it was a couple of years ago, the contact issues not as severe, the ability to recognize pitches sharper. He has a great makeup reputation and has clearly put a lot of work into fixing his flaws. The athleticism and the defense have always been there.
The projection systems (incorporating his minor league data and not just 2015) are not impressed at all: Steamer has him at .236/.290/.404, ZiPS at .228/.279/.405, PECOTA .228/.296/.394. Those slash lines are very similar to what he did in his 75 spring training at-bats.
Ultimately, we cannot expect Thompson to be a .300 hitter or a .290 hitter. If we go solely with the sabermetric projections, he's not even a .240 hitter. However, in his case I think the projection systems are under-estimating him to some extent. It would not surprise me to see Thompson become a .240-.250 hitter down the line, with enough power and defensive contributions to be valuable, perhaps something like Drew Stubbs with fewer steals and more power.