Yeiper De Jesus Castillo Alfonso
- Bats Right, Throws Right
- Height 6' 3", Weight 158 lb.
Yeiper Castillo has been a minor league pitcher.
Castillo was signed by Boston Red Sox scout Ernesto Gomez in November 2005. He was 2-4 with a 4.00 ERA the next summer for the DSL Red Sox. In 2007, he improved to 2-2, 1.83 with a save and 59 strikeouts in 54 innings for the same club. In 2008, the right-hander came to the US with the Lowell Spinners and posted a 3-6, 4.19 record with 62 whiffs in 58 innings. He tied for 6th in the New York-Penn League in losses. He split the next summer between Lowell (6-1, 2.92) and the Greenville Drive (0-4, Sv, 7.04). He tied for 8th in the New York-Penn League in wins.
He went 5-0 with a 3.21 ERA for the Aguilas del Zulia that winter despite 12 walks in 14 innings over 17 relief stints. He tied for third in the Venezuelan League in wins, behind only Carlos Monasterios and Romulo Sanchez. He began 2010 back with Greenville and was 4-5 with a 3.58 ERA before injury sidelined him until late August. He made two rehab stints with the GCL Red Sox (1 R in 3 2/3 IP) then did not pitch in 2011.
Back in action in 2012, Yeiper pitched for Greenville (5-4, 2 Sv, 3.92) and the Salem Red Sox (3-4, 3.17), tying Steven Wright for fourth in the Red Sox chain with 119 strikeouts but also finishing third with 62 walks. In the winter, he was 3-2 with a 2.77 ERA for Zulia. He then moved to the Navegantes del Magallanes for the 2013 Caribbean Series. He was yanked in the 5th inning of his start against the Criollos de Caguas, trailing 2-1; he would take the loss to Efrain Nieves.
- 2012 Red Sox Media Guide