A pinch-hitter is a batter used as a substitute for another batter. A pinch-hitter only comes into the game when the batter whose turn he is taking is due to bat. He is then "announced into the game"; the batter which he replaced is out.
That's the definition of a pinch-hitter.
• Phillies Alumni 
The most prolific pinch-hitter in Phillies history is Greg Gross, a left-handed-hitting outfielder who wore pinstripes from 1979-88. His 17 seasons in the big leagues includes time with the Houston Astros and Chicago Cubs. His 143 career pinch-hits rank fifth in Major League history.
Here are Phillies pinch-hit records. Some of the names are familiar, others not.
Career hits
Greg Gross (117)
Tony Taylor (54)
Tommy Hutton (52)
Greg Dobbs (51)
Tim McCarver (47)
Season hits
Greg Dobbs (22, 2008)
Roy (Doc) Miller (21, 1913)
Career home runs
Cy Williams (9)
Greg Dobbs, Ricky Ledee, Matt Stairs (7)
Season home runs
Gene Freese (5, 1959), Matt Stairs (5, 2009)
Rip Repulski (4, 1998), Del Unser (4, 1979)
Team home runs in one season 
1958 (11)
1984 (10)
2015 (10)