Frank Alfred Linzy (born September 15, 1940) is an American former professional baseball player, used almost exclusively as a relief pitcher.

Over the course of his Major League Baseball (MLB) career, Linzy played for the San Francisco Giants (1963; 1965–1970), St. Louis Cardinals (1970–1971), Milwaukee Brewers (1972–1973), and Philadelphia Phillies (1974).

That year, the hard-throwing righty had arguably his best season, in which he tallied a 9–3 win–loss (W-L) record, 57 games (G), 40 games finished (GF), 21 saves (SV), 812⁄3 innings pitched (IP), allowing 76 hits (H), 19 runs (R), 13 earned runs (ER), 2 home Runs (HR), 23 walks (BB), notching 35 strikeouts (SO), hitting 3 batsmen (HBP), making 5 wild pitches (WP), facing 334 batters (BFP), yielding 8 intentional walks (IBB), and posting a 1.43 earned run average (ERA).

But he was not a "closer," in the modern sense of the word; Linzy was more of a 1960s "fireman," in that the Giants called upon him at any time — not just in the 9th inning — but in the 7th, the 8th, or whenever the opposition was threatening to score late in a tight game.

Linzy's big league totals include a record of 62–57 W-L, 516 G, 2 GS, 342 GF, 110 SV, 8171⁄3 IP, 790 H, 315 R, 259 ER, 35 HR, 282 BB, 358 SO, 14 HBP, 30 WP, 3,454 BFP, 97 IBB, 1 balk (BK), and a 2.85 ERA.