LATROBE, Pa. (AP) -- The whistle blew and Sean Spence sprinted forward, each cathartic step distancing the linebacker from the horrific knee injury that threatened to end his NFL career before it even really began.
Spence almost gleefully smashed into fullback Bryce Davis during the Pittsburgh Steelers' first full contact drill of training camp on Monday. The two tussled for several seconds before Davis - his fists full of Spence's jersey - pulled them both to the ground.
Call it a victory for Spence, in more ways than one. He's a football player again, however unlikely that may have been in the agonizing weeks and months after he shredded his left knee in a 2012 preseason game against Carolina.
The former third-round pick used to watch replays of his knee bending in ways it's not supposed to bend - ripping up his peroneal nerve in the process - as he raced into the Carolina backfield. No longer.
''I don't even revisit it,'' Spence said.
For good reason. Spence spent too many nights crying himself to sleep wondering if he would ever make it all the way back. Sure there were times he doubted he would get this far. He responded by forcing himself to go in for treatment on the days he would have rather stayed home because watching the Steelers prepare for life without him was just too painful.
Slowly, his surgically repaired knee regained strength. Amazingly, the nerve regenerated. The 24-year-old Spence looked as quick as ever during organized team activities during the spring, but he knew Monday would be the day of reckoning.
The Steelers begin the contact portion of training camp at Saint Vincent College with ''backs on backers,'' which is just as basic - and as violent - as it sounds. A linebacker bolts toward the quarterback, with a running back or tight end the only thing in his way. It's a chance for rookies to make a name for themselves and veterans to show they've still got it.
For Spence, it was a homecoming.
''I was anxious,'' he said. ''I was chomping at the bit.''
It showed. He plowed into the breach again and again, winning some battles and losing others. Not that it mattered. He'll have plenty of time over the next month to prove he's worthy of a spot on the 53-man roster. Monday was simply about returning to the game he worried was gone for good.
''I was never a person who would quit,'' Spence said. ''I'm never going to be that person.''
Coach Mike Tomlin certainly isn't concerned. Standing a few yards away while Spence competed in just his second padded practice in two years - his initial comeback last fall was cut short by a broken finger - it hardly registered to Tomlin that Spence's long road back had reached its destination.
''We've had a great deal of comfort on where he is for some time,'' Tomlin said.
It's a sense of comfort Spence doesn't take for granted. Considering the odds Spence faced as he laid on the Heinz Field turf in agony two summers ago, he knows many teams would not have invested the money or the time on what could have been a fruitless enterprise.
''They could have given up on me a long time ago,'' Spence said. ''I'm just so thankful.''
And so eager to pay that patience back. The one blessing of his injury is that it forced him to watch more football than he ever has in his life. While it may take a bit for him to get fully comfortable throwing his body around, there is little doubt Spence knows where to go when he's on the field.
The speed that overwhelmed him as a rookie has slowed to a more reasonable pace. It may be the one advantage he has over rookie Ryan Shazier, taken with the 15th overall pick in May to fill the job the Steelers expected would have been Spence's at this point if fate had not intervened.
The starting job next to Lawrence Timmons for the season opener against Cleveland is Shazier's to lose. Spence understands what he's up against but isn't ceding anything. He stressed he's ''just here competing.'' For now, that's enough.
''Soon as I got the first hit, I was good to go,'' he said, ''like back to football.''
NOTES: Steelers general manager Kevin Colbert said the team has some money to play with under the salary cap and could sign one of its impending free agents - including linebacker Jason Worilds or cornerback Cortez Allen - to a long-term deal before camp breaks. ... Rookie LB Jordan Zumwalt left practice early with a groin injury. ... The Steelers are off Tuesday.
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