TAMPA — Four Bucs players injured in Sunday's loss at Arizona were absent from Wednesday's practice, but LT Donovan Smith , who hasn't missed a snap in his 18-game career, watched practice due to a hip injury.The severity of the injury is unknown; coach Dirk Koetter declined to share any more injury information than he's required. The Bucs face the real prospect of being without the four players injured Sunday — RB Doug Martin (hamstring), DE Robert Ayers (ankle), TE Luke Stocker (ankle) and WR Cecil Shorts (hamstring).If Smith can't go, the Bucs could plug Evan Smith in at left guard and slide Kevin Pamphile to left tackle, or they could plug in veteran backup Gosder Cherilus . The backup left tackle on the depth chart is undrafted rookie Leonard Wester , who has been inactive in the first two games.TRANSACTION: The only roster move in response to those injuries so far came at receiver, where Freddie Martino , 25, was promoted from the practice squad to add depth in anticipation of Shorts not being able to play.Martino had six catches for 65 yards in the final 10 minutes of the final preseason game. He played in one game for Atlanta in 2014 (where Koetter was offensive coordinator) for two plays, with no catches.The Bucs also waived LB Josh Keyes from the roster and signed former Purdue and Cowboys DE Ryan Russell to the practice squad.BRIGHT SPOT: One area of emphasis for Koetter was lowering the frequency of penalties against the Bucs, who had the second-most penalty yards (74.7 per game) last season and were tied for the most penalties (8.9 per game).Through two games, the Bucs are in the league's bottom 10 in both, averaging 5.5 penalties for 43.5 yards, to Koetter's pleasure."Our goal is to be six or less a game, and we've made it," Koetter said. "We have done a pretty good job in that area, and we need to continue that."THIS AND THAT: If Ayers can't go Sunday, undrafted rookie DE Channing Ward , inactive for the first two games, would likely dress as the fifth end. "You sit on the sideline and watch and say, 'If I keep working hard, that could be me,' " said Ward, who played at Ole Miss. "Right now, I have an opportunity this week to go out there and play, so I have to take advantage of it." … Rookie LB Davonte Bond , inactive the first two games as he recovers from a preseason hamstring injury, said the time off has helped him prepare mentally. With Keyes cut, he's likely to make his debut Sunday. "I'm feeling good now and definitely excited to play," he said. "I know mentally I've picked up a lot, learned a lot more of the defense. I had to take that serious while I was sitting out and get the mental reps."Contact Greg Auman at email@example.com and (813) 310-2690. Follow @gregauman.