Spencer Turnbull should leave the Arizona Fall League feeling good. Ex-Madison Central High star Turnbull, a Detroit prospect pitching for Salt River, threw four shutout innings on Monday in what may have been his last outing. The 6-foot-3 right-hander had an injury-interrupted 2016 season and started slowly in the AFL but with back-to-back strong starts has trimmed his ERA to 3.60. He has 20 strikeouts in 20 innings and has not yielded a home run. Turnbull’s velocity reportedly has been a little down this fall, but that’s not necessarily a bad thing. “I’m learning how to pitch with a little less velocity,” Turnbull said in an mlb.com article. “I’m sinking it and cutting it more than I used to rather than throwing heaters down the middle.” Turnbull, 24, is rated Detroit’s No. 12 prospect by mlb.com but is likely still a couple of years away from a big league shot. He is 12-7 with a 3.32 ERA in his three pro seasons and is expected to pitch in Double-A in 2017. It’s seems odd now that Turnbull was undrafted in 2011 out of Madison Central, where was a standout hitter and hurler. He went to Alabama and left in 2014 as a second-round pick by the Tigers. … Former Mississippi Braves standout Dustin Peterson hit his first AFL homer in support of Turnbull on Monday. Peterson is batting .328 for the Rafters after an MVP-caliber year in the Southern League (.282, 12 homers, 88 RBIs). Richton’s JaCoby Jones, also a Tigers prospect, had three hits for Salt River and is up to .370. … Petal High product Anthony Alford (Toronto) stole three bags for Mesa on Monday and now has eight this fall.