PITTSBURGH — Jordy Nelson caught the ball, spun and prepared to dart downfield.Two steps later, Green Bay's Pro Bowl wide receiver was on the turf, his left knee injured and his season very much in doubt. Nelson gingerly walked to the sideline early in the first quarter of Sunday's 24-19 preseason loss to Pittsburgh, which might be the last sign of Nelson in his familiar No. 87 jersey this year.The Steelers had a severe injury to a crucial player as well, as Pro Bowl center and former Florida star Maurkice Pouncey exited in the first quarter. The Pittsburgh Post-Gazette reported that Pouncey will be out for an extended period with a broken fibula above his left ankle.The former Gator missed tore multiple ligaments in his right knee in the 2013 opener and missed the rest of the season.Nelson, who according to NFL Media has a torn ACL, is scheduled to be re-evaluated today in Green Bay. While Packers coach Mike McCarthy stressed the defending NFC North champions "will look for good news," quarterback Aaron Rodgers expressed equal parts frustration and mystification."It's difficult to lose a guy like that in a meaningless game," Rodgers said.On Green Bay's opening drive, Rodgers hit Nelson on a hitch route. Nelson leaped to make the catch and planted his left leg while turning to face Pittsburgh cornerback Antwon Blake only to unexpectedly drop to his knees.Nelson set career highs in receptions (98) and yards receiving (1,519) in 2014."I'm not going to get into the 'What if' game," Rodgers said. "I don't know what his status will be. I'm just hoping for the best."Rodgers completed 4-of-5 passes for 57 yards during two series. One drive ended with a touchdown run by Eddie Lacy and the other with Rodgers getting sacked by Steelers linebacker James Harrison for a safety. Ben Roethlisberger was 11-of-14 for 100 yards and a score which put the Steelers ahead 9-8 before the reserves took over. RG3 back: Robert Griffin III returned to practice, three days after the Washington quarterback left the preseason game against Detroit because of a concussion. Griffin fully participated in individual, 7-on-7 and 11-on-11 drills during a session of about two hours at Redskins Park. "He'll be checked by a neurosurgeon later this week to determine whether he'll be cleared for (Saturday's game against the Ravens), but so far so good," coach Jay Gruden said. "He didn't have any headaches or anything of that nature." Falcons: Roddy White will have minor surgery on his right elbow, coach Dan Quinn said, though the receiver should be ready for the Sept. 14 opener against Philadelphia. White, 33, developed some unexpected swelling last week and didn't play Friday against the Jets. Giants: Starting safety Bennett Jackson torn an ACL on Saturday against the Jaguars and is out for the season and free-agent safety Justin Currie broke his right ankle and fibula earlier in the game. Starting middle linebacker Jon Beason said he does not consider his sprained left knee injury serious and hopes to be back to start the regular season. Panthers: Defensive end Frank Alexander is out for the season with a torn Achilles and is slated for surgery on Tuesday.