Austin, 26, hit .235 with four home runs in 34 at-bats this spring.
McKinney, 23, showed power early on in camp by clubbing four homers, but struggled as of late, lowering his batting average to .161 in 31 at-bats.
Gallegos, 26, looked good at times but struggled as well. The Mexican was 0-0 with a 3.68 ERA in eight games.
Heller, 26, pitched extremely well for most of the spring, however, he allowed four earned runs in his last 5.2 innings pitched. His latest blunder came on Tuesday against Detroit, when he permitted three runs in 1.2 innings. In all, Heller struck out 14 and posted a 4.22 ERA in 10.2 innings pitched.
The moves appear to seem that New York will carry 13 pitchers to begin the season next week in Toronto. With Jacoby Ellsbury set to begin the season on the DL, Austin and McKinney were the two best options, position-player wise, to replace him on the 25-man roster.
German, 25, has pitched to a 0-0 record with a 2.34 ERA, and a 1.34 WHIP so far this spring. The Dominican Republic native has thrown 12.2 innings and compiled 14 strikeouts.
Holder, 24, has tossed an even 10 innings this spring and held opponents to a 1.10 WHIP. He is 0-0 with 11 K’s and owns a 1.80 ERA.