As compared to his usual steely demeanor, Pittsburgh Steelers G David DeCastro was downright giddy Monday at the Steelers' practice facility.

Odd for a day in which the rookie was moving around on crutches and in a large knee brace. Odder still on the day of the first NFL practice he would miss due to injury -- one that could have him out of action for a significant period of time.  

But perhaps there was good reason for the relatively cheery disposition.   

OL coach Sean Kugler told the Pittsburgh Tribune-Review on Monday that DeCastro will not be placed on injured reserve.   

"Fortunately, he's not done for the year," Kugler told the Trib immediately after practice. "It is going to be a long comeback for him, but just the fact that it wasn't something devastating that ended his year (is positive). ... I think David will be back this year, and he's intent on doing that; I know that."

Before practice, DeCastro participated in team meetings and went through what was seemingly a normal practice day -- other than the crutches and the brace. 

"He had a smile on his face, and he was joking around with the guys as normal," C Maurkice Pouncey said. "And hopefully it stays that way."   

Smiles? Joking? This is the player the affable Pouncey dubbed "Mr. Personality" early in camp because of his no-nonsense, businesslike ways.   

Coach Mike Tomlin was asked if DeCastro was able to remain upbeat on a day like Monday.   

"For DeCastro, (yes)," Tomlin said.

Tomlin was then asked if he was surprised that the Stanford product was upbeat.      

"Well, those of you who know DeCastro, know that 'upbeat' for him is a stretch," Tomlin said. 

Earlier in the day, DeCastro sat back in a chair in the team facility's lobby. He nodded when asked if he was upbeat and cracked a smile. Knowing that Tomlin has a strict nobody-talks-about-injuries-publicly policy, he could only say, "I don't know," when asked if he was out for the season.   

"Unfortunately, (the injury) happened, but the next man will step up and fill the position," reserve OL Doug Legursky said. "That's what we've shown through the years. The next man has to step up and the standard is the standard. That's what we embrace around here."

In this case, it's Ramon Foster who is the "next man." Foster has started at least four games every season since joining the Steelers as an undrafted rookie free agent from Tennessee in 2009. Despite never going into training camp as a starter, he has started 26 games in three seasons at guard.   

"It's just good to be that guy," Foster said. "'The more you can do' is one of Coach Mike Tomlin's main things, and it's shown a lot lately -- at least since I've been here and with other guys, too."

Foster was a tackle in college and started at right tackle for the Steelers' preseason game against the Colts on Aug. 19. But he has played almost exclusively guard during the regular season with the Steelers.   

DeCastro will have surgery Wednesday, according to Tomlin. On Sunday, ESPN cited sources in reporting that DeCastro tore his medial collateral ligament and suffered some damage to his patellar tendon. But the ACL is intact, according to ESPN's sources.

On Friday, the Steelers must make 22 cuts to get their roster down to the regular-season standard of 53. If DeCastro is placed on IR, he's done for the season. If he's not, a roster spot must be used on him that could have been available for another player.

Follow Steelers reporter Chris Adamski on Twitter @CBSSportsNFLPIT and @BuzzsawPGH.