[2][3] Kraus, born in San Antonio, Texas, was a left-hander listed as 6 feet 4 inches (1.93 m) tall and 190 pounds (86 kg).

His rookie season in the majors, 1943, was his finest; he posted a losing, 9–15 won–lost record for a Philadelphia team that finished at 64–90, but he compiled a solid 3.16 earned run average in 1992⁄3 innings pitched.

When he returned to the Phils from the Army in 1945 he was much less effective, dropping nine of 13 decisions and putting up a mediocre 5.40 ERA.

The following year, as a Giant, he was almost exclusively a relief pitcher; appearing in 17 games, he won two and lost one, but his ERA continued to climb, to 6.12.

In 3061⁄3 innings pitched, he allowed 318 hits, 133 bases on balls, and 136 earned runs; he fanned 83.