The San Francisco Giants apparently wanted to give Chris Stratton a new challenge. They should be pleased with his response. Stratton, the former Mississippi State ace from Tupelo, made his Double-A debut on Wednesday and allowed one run on seven hits (one home run) and two walks in five innings. He struck out three for the Richmond Flying Squirrels, who ultimately lost to Harrisburg in 13 innings. Stratton, 23, a 6-foot-3 right-hander rated the No. 4 prospect in the Giants’ system by mlb.com, seemed to be treading water this year, his second full pro season. He was just 7-8 with a 5.07 ERA in 19 games at high Class A San Jose before his promotion. At low-A Augusta in 2013, Stratton went 9-3, 3.27. He was the SEC pitcher of the year in 2012 and was drafted 20th overall that year by the Giants.