“‘With [Dick] Groat back from service, we’ll have that middle well plugged up and that should make our pitchers that much better. [Frank] Thomas can really go and get them in center. [Jack] Shepard came nicely last year as both a catcher and a hitter. So for the first time since I’ve had the club, I’d say we’re solid up the middle,’ Fred [Haney] asserted.” Quoted by Ritter Collett, Journal Herald (Dayton, OH), March 24, 1955, p6
- NOTE: There are a couple of earlier uses of the term in the 1950s, but they seem to refer only to the middle infield. This is the earliest I’ve found that refers to the catcher and center fielder as well. Solid up the middle or not, Haney’s Pirates finished dead last in the NL that year.
No earliest use given in 2009 Dickson Baseball Dictionary