"So which potential big-impact free agent should the Cubs pursue when that one-year, ''pillow'' contract with first baseman Carlos Pena expires?

Albert Pujols? Prince Fielder?

What about Pena?

''That'd be great,'' said outfielder Tyler Colvin, who has spent as much time with Pena as anyone in camp, as he learns to play first base for possible backup work. ''He's definitely a presence in the clubhouse that everybody likes. He's going to help us a lot this year, and if he wants to come back, great. We could definitely use him.''

Pena hasn't even played a game that counts yet for the Cubs. And he's coming off a .196 season for Tampa Bay. And as Colvin was speaking, Pena was sitting on a 1-for-9 start.

But in just three weeks in a Cubs uniform, Pena has already started playing the role of difference-maker, especially in a clubhouse — and, at times, dugout — that has been in search of the right chemistry mix since that 97-win season in 2008.

The addition of Marlon Byrd last year was a major stride in the right direction, and the Cubs brought back respected clubhouse favorites Kerry Wood and Reed Johnson over the winter.

But just as important has been the free-agent signing of Pena, at least in large part because of the major team figure he replaced, Derrek Lee. Pena has made a point to be available to younger players, and also brought energy and ideas even to typically mundane fundamentals work this spring.

''Different personalities, both great guys,'' said catcher Geovany Soto, comparing the new first baseman to the predecessor Soto called more of a ''silent leader'' known for helping stabilize the clubhouse behind the scenes. ''We're fortunate to get great players like Marlon and Pena, who are great in the clubhouse.''

Their value took on a more tangible look in the aftermath of Wednesday's Carlos Silva-Aramis Ramirez dugout scuffle — when Byrd and Pena pulled together a players-only meeting Thursday morning that guys later said was productive and helped reinforce manager Mike Quade's message of unity in their purpose."