Lamb graduated from Housatonic Valley Regional High School — also the alma mater of star Pirates' right-hander and brother-in-law Steve Blass — in 1964.

In 1969, he enjoyed a breakout season with Salem of the Class-A Carolina League, appearing in 50 games, all in relief, and posting an 11–4 won–lost record and 18 saves, with a sparkling 1.95 earned run average.

He followed that campaign with another strong year in 1970, with a combined 6–2 record, 15 saves, and 1.17 earned run average in 39 games in Double-A and Triple-A.

The Pirates captured the division title, but Lamb did not appear in the 1970 National League Championship Series, won by the Cincinnati Reds in three straight games.

But he turned things around in 1973, winning all six decisions with 12 saves and a 1.66 ERA in 31 games for Charleston, earning one last promotion to the Pirates in midsummer.