TRENTON – Thunder catcher Austin Romine has a “mild” concussion, Yankees head of player development Mark Newman told The Trentonian, and will be out “a minimum of 7 days from the time of the injury.”

The injury occurred last Thursday, when Altoona designated hitter Travis Scott barreled over Romine toward the end of Trenton’s loss to the Curve. Romine stayed in the game at the time, but sat out the rest of the series before being placed on the disabled list on Monday.

When he spoke to the media on Saturday, he said his back and neck felt stiff but that he wasn’t worried about a concussion, even with the knowledge that the team and its medical staff hadn’t ruled it out as a possibility.

He is eligible to come off the shelf on Monday, when the team has an off day before a three-game set against Harrisburg at Waterfront Park.

Because concussions have such a wide spectrum of severity, it is difficult to say when Romine will likely make his return. Justin Morneau was concussed last July and missed the rest of the season. On the other hand, Red Sox pitcher Josh Beckett didn’t miss any of the regular year after being hit in the head during spring training and experiencing symptoms of a concussion.

In other Thunder news, ace reliever Tim Norton has been promoted to Triple-A Scranton, leaving a gaping hole in the back of the team’s bullpen. Over his last 10 games, Norton, 29, had allowed just four hits over 12 1/3 innings, and had struck out 20 against just two walks.

Overall, the right-hander leaves Trenton with a 1-0 record, a 1.55 ERA and an astounding 44 strikeouts in 29 innings. He leads Eastern League relievers in batting average against (.124), strikeouts per nine innings (13.66) and fewest baserunners per nine innings (7.14).