Sosa was 22-years-of-age when he got his first taste of the Majors in ‘72, going 0-1 with a nice 2.30 earned run average over 15.2 innings for the San Francisco Giants.
In 1973 he would have an excellent year, going 10-4 over 71 appearances, posting an ERA of 3.28 with 18 saves as an official rookie, pitching 107 innings and making one start.
He would go on to have a very nice, under-the-radar Major League career that spanned 12 seasons, between 1972 and 1983, going 59-51 with 83 saves and a 3.32 ERA in 601 appearances.
His finest season would arguably be 1979 while with the Expos when he went 8-7 with a brilliant 1.96 ERA over 62 appearances and 96.2 innings pitched, along with 18 saves while closing out 41 games.
He would play for eight different teams, including the Los Angeles Dodgers for whom he’d get the only World Series experience of his career in 1977, and the Montreal Expos where he’d see the only other Post Season action in 1981.
Seems the 1970’s had a bunch of these “forgotten” relievers who put in solid seasons year after year, without the gaudy numbers but effective nevertheless.