Terrance Gore made his Major League debut in 2014. He tallied just his third plate appearance last night, and is still seeking his first hit. He reached base after being hit by a pitch last year, but he's still awaiting that first elusive grounder up the middle. There's a serious chance that he may not get a hit this season either. That would be an incredibly rare feat for a player that started 2014 in A-ball, skipped Double-A and was an important part of the Royals' World Series roster. Yet here we are, and such is baseball!
As you probably know, Gore became one of Ned Yost's favorite toys because of his speed. He has legitimate 80-grade wheels, and he can use them to devastating effect. Gore was deployed as a pinch runner extraordinaire alongside Jarrod Dyson; the pair combined with the reliever trifecta of Kelvin Herrera, Wade Davis and Greg Holland to form one of the most unique playoff juggernauts ever seen. Gore is now back with the yearly round of September call-ups, and it stands to reason that Yost will once again include him on his playoff roster.
Gore's resumed presence in Kansas City leads one to wonder if there are any other players in the league that are here because of one outstanding tool. There are some players such as Joey Gallo and Billy Hamilton that rise to the limelight due to one overwhelming tool that they possess, but both Gallo and Hamilton have other positive qualities than their power and speed, respectively.
Gallo has a strong throwing arm, and Hamilton turned out to be a fairly good center fielder. In fact, Gore himself plays the outfield decently well. What Gore probably can't do is hit. He's never been an average hitter (or anything close) at any level of the minor leagues he's posted a sizable amount of plate appearances. In 259 plate appearances at double-A, Gore hit .284/.367/.311, which amounted to a 97 wRC+. He actually walked in a tenth of his plate appearances as well, and has demonstrated solid walk rates in the past. Gore may sneak in some singles but won't hit for any power and is unlikely to muster any extra base hits beyond stretching singles into doubles.
Are there more one trick ponies like Gore? Quintin Berry is back in the majors filling the same role as Gore, but that's not fun enough for our purposes. We want to find players that are sticking around with only one major tool.
To recap, the five main tools are "hit," "run," "field," "throw," and "power." It is impossible to be a big leaguer if your only good tool is your throwing arm. One is tempted to think of Jeff Francouer, but Frenchy also hits dingers. The idea of a player with consistent hitting as his only tool is interesting, and it calls to mind something like last year's version of Billy Butler, Gore's former teammate. Butler posted a .271/.323/.379 slash without displaying a knack for anything else at all but still managed to be a 97 wRC+ player. A lack of power combined with a complete lack of speed will do that, and even then that slash line hardly screams of an overwhelming hit tool.
A late-career Tony Gwynn could possibly fit this mold, as he had lost a healthy portion of his plus baserunning and fielding at that point. In 1999, Gwynn put together a 2.1 fWAR season by hitting .338/.381/.477. Because this was the insane run-scoring environment of the late 90s, that was good enough to score Gwynn only a 123 wRC+, but there's little doubt he was an 80-grade hitter.
Pure fielders are a bit harder to quantify. The best outfielders often are blessed with great speed, so we cannot truly call them one-tool players. The same is true for most infielders. Even Jose Molina, being a member of the Molina clan, had a great throwing arm in addition to his God-given abilities behind the plate. So it is likely impossible to have only a fielding tool. The player would have to basically be a defensive positioning savant in left field, be without any hitting ability, and have the arm of Jacoby Ellsbury.
That leaves us with power. There are a small handful of players that can only lay claim to power as a plus tool. Evan Gattis, Chris Carter, and Justin Smoak fall into this category, yet none of them is in the upper echelon of the ISO rankings. It would theoretically be possible to survive in the big leagues with nothing but an 80-grade power tool at one's disposal, and Joey Gallo is probably going to see if it can be done. However, no such player exists in today's game.
It would seem that Terrance Gore is the only possessor of a lone tool that ranks among the hyper-elite. The fact that his tool is neither hitting nor power is the reason why he's been so far relegated to the role of postseason curiosity.
Speed kills. We know this because we watched the Royals last year. We 'know what speed do'. It just seems that it doesn't do enough to keep Terrance Gore in the major leagues for a long tenure...it seems that a lone tool, even one that ranks at an 80-grade, won't keep anybody in the bigs.