Pena, a Georgetown alumnus, was bought from the Worcester Tornadoes.
Pena, 22, went 2-4 with a 5.08 ERA for the Tornadoes last year. In 67.1 innings, he allowed 76 hits while walking 17 and striking out 60. Opponents had a .286 average against in his 32 appearances.
"Submarine pitcher with a good changeup," Bill Bryk, the Padres' minor league field coordinator, explained of Pena.
"More of a submarine deliver and doesn't throw as hard (as Koch)," Padres Independent League scouting coordinator Mal Fichman added. "Pena had good control. The ball sank well on his pitches. Good changeup. He has to learn how to get lefties out."
The Padres acquired Koch from the Brockton Rox. Koch was originally a 32nd round draft pick out of Lake City (FL) Community College by the Minnesota Twins. He pitched one season for the Twins Gulf Coast League affiliate in 2003 going 2-3 with a 2.73 ERA.
Koch, 22, spent two seasons with the Rox, going 5-5 with a 3.45 ERA and 62 strikeouts in 78.1 innings this past year.
"He can get up to 92-93 with his fastball and he has a pretty good slider," Bryk said of Koch. "We got good reports on his makeup."
"More of a power pitcher, fastball, slider," said Fichman. "Heavy fastball with some sink. Good breaking ball. He needs a good changeup."
"He has a great arm," Bryk explained. "He had a cannon in camp. I don't how much he will hit but his defense and arm are great."