Bucs CB Brent Grimes was back at practice Saturday after missing 11 days with an undisclosed injury, and help can't get there soon enough for a Tampa Bay secondary depleted by injuries."We're thin," coach Dirk Koetter said, with Vernon Hargreaves out with a groin injury and Javien Elliott sidelined with an undisclosed injury. "Last week and continuing into this week, offensive tackle we'er thin, and we're thin in the secondary, especially at corner. We just signed two corners yesterday; if we wouldn't have signed those guys, we would have had four corners to practice today. It would have been tough."The Bucs were shorthanded enough that starting safety Justin Evans stepped in as the starting nickel corner Saturday, with rookie Jordan Whitehead taking his place as a starting safety.Video: Peyton Barber runs this morning, and Bucs defense has makeshift look with safety Justin Evans filling in as nickel, rookie Jordan Whitehead in his spot at safety. pic.twitter.com/0p3MuL3T2n— Greg Auman (@gregauman) August 11, 2018The Bucs added two undrafted rookies in Central Michigan's Amari Coleman and Georgia's Aaron Davis, who made their practice debut Saturday."You've got to keep going, and the two new guys got baptism by fire," Koetter said. "They got a lot of reps today."Second-round picks M.J. Stewart and Carlton Davis both played extensively Thursday, getting among the highest snaps on the defense. Grimes could be back on the field for Saturday's preseason game at the Titans, but the Bucs will lean on their youngest corners extensively this week.