Here's a reply from a self confessed lifetime "shortstop".
A good player who can beat all the locals, but can't quite get there when a strong roadman comes thru town. Needs a little weight from the top players.
Like me for instance, I was the best player in Bakersfield and the whole San Joaquin Valley in California in the 70's, but when guys like Lisciotti, Marino, Billy Johnson, Cole and Peter Gunn came thru, I couldn't handle them. Peter Gunn and I had several long battles, but he always got me in the end.
I did beat Cole with weight (9-6 in One Pocket) and many other good players. Among them Billy Ray, Artesia Kenny, Cuban Joe, Wino Richard, Ron Mackey, Waterdog, Little George from Fresno, Liveta, and a couple dozen others whose names escape me. New York Blackie tried spotting me the Seven and gave up quick. And I beat Hippie Jimmy Reid with the Eight and the break. And I got a young cocky kid named Keith to spot me the Eight and he didn't like it (he was maybe 16 then). Later on Keith gave me the Eight and bar-b-qued me.
Same when I lived in Hollywood in the late 60's. I played everyone who came into the Billiard Den and beat almost all of them. Lost to Jimmy Reid, Bob Osborne and Youngblood among others. Youngblood gave me one bank on a short rack (I had to make four) and we played all day and night. I couldn't believe a young kid (he was maybe 18 or 19) could give me that game. He turned out to be a great one, one of the best bankers alive.
So being called a "shortstop" ain't all bad. It means you have a speed and are considered a "player" and not a faker.