Detroit — We already know Tigers’ president Scott Harris leaves no stone unturned when it comes to adding talent, even if it’s potential-based.That explains the signing of 24-year-old outfielder Caleb Shpur to a minor-league contract. Most likely, he will be spending some development time in the Florida Coast League, but it’s easy to see why he caught the Tigers’ attention.The Connecticut native went undrafted after six years of college baseball. He spent four years at Endicott College in Massachusetts and two at University of Connecticut and he was an on-base machine every year, posting a career on-base average of .432.Last year at UConn, he slashed .358/.426/.521 with a .997 OPS, helping the Huskies to a 38-21 record.