John Harbaugh has said that the race to be the Baltimore Ravens' starting centre will be a "great battle".
The Super Bowl champions have a vacancy at centre following Matt Birk's retirement earlier this year, with Gino Gradkowski and AQ Shipley competing at the position.
The head coach told the team's website: "They're both playing really well right now. They're both very similar. They're very athletic. They're very quick.
"They're very smart centers. They've [both] gotten us in the right protection. They've gotten the run calls made correctly. So it's going to be a great battle."
Gradkowski spent his rookie season as Birk's understudy, while Shipley was acquired in a trade with the Indianapolis Colts in May.
