Cederlind, a right-hander from Merced College, signed for $285,000. He was selected 165th overall in 2016 after being drafted by the Twins in the 22nd round a year ago.
He elected to return to school and went 5-2 with a 3.75 ERA in 23 appearances, four of which were starts. Over 57 2/3 innings, he compiled 63 strikeouts against 34 walks.
Cederlind is said to wield a mid-90s fastball.
Gibbs signed for $150,000. The catcher hit .396/.497/.590 with five homers and 15 walks at Central Arizona College and is known for his strong arm. He was slated to play next season at the University of Southern California.
Prohoroff, a right-hander from Cal State Fullerton, signed for $160,000. Prohoroff had a 0.68 ERA in 20 relief appearances this year, with 30 strikeouts over 26 1/3 innings.
Eagan, an outfielder from the University of Arkansas, also signed for $160,000. Eagan's best tool is his power, and he had eight doubles and seven home runs in 55 games as a junior this season.
Joshua Needelman is a reporter for MLB.com based in New York. This story was not subject to the approval of Major League Baseball or its clubs.