"I think he's done really well," coach John Harbaugh said Friday, according to the Ravens' official website. "I just talked to him. He told me he felt very good today. I think we'll wait until game time, just to see for sure. (We'll) see how it feels up there with the weather and everything and make a decision right before the game."
Heap is apt to take a careful approach after coming back too soon from a hamstring injury in 2007. He aggravated that injury and was limited to just six games.
"I went through it a couple years back, four years ago, and when I did it the first time, I came back too early and probably hurt myself and ended up missing a lot of that season," Heap said. "So, you kind of know what it's like.
"You're not ever going to get up to the type of speed that you will in a game in practice. It just doesn't happen. It's just an extra gear that you get to. So, like I said, I'm going to test it out on Sunday and just be smart. ... We're at the point of the season where you have a couple of goals, and one of them (making the playoffs) is right in front of us. I've got to be smart how we go about it. We'll see what happens."
Harbaugh believes Zbikowski can play again this season.
"He doesn't have anything radiating into his legs, so that's a very good sign," the coach said. "There might be a little bit of a ligament strain in there that we treated with some cortisone this week. So, we think we've got a chance to get him back. We just have to see how it responds to that."
Center Matt Birk (knee), linebacker Brendon Ayanbadejo (knee), defensive end Cory Redding (elbow), and wide receivers Marcus Smith (shoulder) and Derrick Mason (ankle) round out the probables for Baltimore.