If you listened closely when Matthew Stafford’s left hand hit the helmet of Raiders DE David Tollefson during the second quarter of Detroit’s 31-20 loss to Oakland on Saturday, you could almost hear Lions fans collective gasp as they wondered about the severity of the injury.

They didn’t dare breathe again until the team said after the game that X-rays on Stafford’s hand were negative, and Stafford said he would’ve returned to action if the injury had happened in a regular-season game.

"[The hand] feels OK right now,” he told Mlive.com. “It's scary to look down [after the injury] and see your hand swell up by the second."

Stafford was 8 for 10 passing for 68 yards before the injury.

Stafford wasn’t the only Lions player who was injured during Saturday’s game. RB Kevin Smith’s day was ended early by an ankle injury, but he said after the game that X-rays were negative. "It just gets scary under the pile of those big guys laying on you,” Smith told Mlive.com. “It's just a minor tweak, something I'm pretty sure I can get rid of quick.”

CBs Chris Houston (ankle) and CB Bill Bentley (shoulder) also left Saturday’s game with injuries. Jim Schwartz said both players will be evaluated Sunday.

Schwartz not impressed by porous second-half defense: The Lions’ starting defense gave up its first touchdown of the preseason Saturday when Oakland’s Darren McFadden scored on a 1-yard run in the second quarter, but the overall performance of the top defensive unit was solid. Detroit’s defensive reserves, however, put forth an effort worthy of a postgame rebuke from Schwartz. “We played poorly on defense after halftime," he said. Detroit allowed Oakland’s reserve QB Terrelle Pryor to rush for a touchdown and throw for two more. Pryor’s 227 yards of total offense were made possible by poor secondary play from CBs Jonte Green and Alphonso Smith, and poor technique from Lions linebackers Schwartz said the performance didn’t help the cases of several players fighting for roster spots. “We’ve got guys out there who are trying to make the team, and they didn’t impress anybody,” he told WXYT radio.

Willie Young continues to impress: If Detroit handed out awards based on preseason performances, DE Willie Young would have a nearly unassailable case for MVP honors. Young intercepted a Carson Palmer pass in the second quarter Saturday by getting penetration into the Raiders’ backfield and deflecting the pass to himself. The move wasn’t surprising, because he has made the same type of interception twice during camp practices. Young has forced a rapid change of possession in each of Detroit’s preseason games. He blocked a punt vs. Baltimore, and forced a fumble in the preseason opener vs. Cleveland.

Leshoure 'does good things' in NFL debut: If Saturday’s game wasn’t RB Mikel Leshoure’s long-awaited NFL debut, his five rushes for one yard would be viewed as a horrible effort. Instead, it will be remembered as a major step in his rehab process. Leshoure said he felt fine after the game, and that the hamstring injury that caused him to miss 13 days of camp was behind him. While Leshoure said his off-field work with the Lions prepared him for his debut, he admitted that one aspect of the game can’t be simulated in the film room. “The speed of the game is something you can’t understand until you’re out there,” he said. "That’s something I’m going to have to get comfortable with.”

Schwartz said he thought Leshoure “did some good things” Saturday, but he wasn’t happy with the Lions’ rushing performance as a whole. Detroit gained just 65 yards on 24 carries (2.7 ypc). Schwartz placed the blame for the poor rushing output on the entire offense. “[The rushing performance] is the fault of the blocking of the O-line, the tight ends, everybody,” he told WXYT radio “We didn’t run the ball at all.”

Special teams shines in loss: Detroit’s special teams units are normally a lightning rod for criticism, but their performance Saturday may have been the biggest positive drawn from the defeat. Eight days after the coverage unit allowed the Ravens to return two kicks for touchdowns that were nullified by questionable penalties, they held the Raiders to an average starting field position of the Oakland 23-yard line. Ronnell Lewis, who was drafted in part because of his special teams prowess, was instrumental in containing Raiders returners. Detroit’s return game was bolstered by an 80-yard runback by CB Justin Miller.

Follow Lions reporter John Kreger on Twitter at @CBSSportsNFLDET and @JohnKreger.