Jackie Bradley Jr. entered spring training as "the guy" in center field and "I don't think anything has radically changed that thought," Boston Red Sox manager John Farrell said Saturday.

Bradley has in the team's lineup almost every game this spring as he works on being more aggressive both in the strike zone and on the basepaths.

Both Bradley and Grady Sizemore could be with the big league club on opening day, "but there are also limits to the roster," Farrell said.

Sizemore was in the team's lineup, hitting leadoff and playing center field for Saturday night's game against the Philadelphia Phillies.

"We can't deny the thought that Grady Sizemore has looked very well in camp," Farrell said. "We're still in the process of trying to get our arms around his durability. We'll extend him a little bit tonight, where he's going to go, maybe seven to eight innings tonight, possibly a full game. So we're starting to get a little more of a test, and maybe answers to some of those tests."