The Ravens changed long snappers Thursday afternoon, signing Patrick Scales and sending Kevin McDermott to injured reserve with an elbow injury.
Baltimore signed McDermott on Oct. 20 to step in for Morgan Cox after Cox suffered a season-ending knee injury.
McDermott had snapped without any issues, but had a high snap last Sunday against the Jacksonville Jaguars. Holder Sam Koch still got the snap down, but the timing on the kick was a bit off and kicker Justin Tucker hooked a 54-yard attempt left and short.
Scales has spent time with the Ravens in two previous training camps in 2011 and 2012, so Baltimore knows him well. He was part of the tryout along with McDermott back in October, but the Ravens picked McDermott.
"Patrick is a guy that was with us in training camp twice who we have a lot of respect for, as well," Harbaugh said at the time. "Both of those guys had excellent workouts and we feel like either one of those guys would fit us really well."
Scales will have to get on the same page in a hurry as the Ravens face the Texans in just three days.
He has never snapped in an NFL regular-season game, but has been around the game since 2011. He's been on four different teams and played in 10 preseason games. He was last with the New York Jets in 2013.
Baltimore has now sent 17 players to injured reserve this year. The most during the Harbaugh era was 19 in 2008.
The Ravens also made a change on their practice squad, releasing tight end Emmanuel Ogbuehi and signing running back Tauren Poole.
Poole is a Tennessee product who went undrafted in 2012. The 5-foot-10, 210-pounder originally signed with the Carolina Panthers and has bounced between them, the Colts, the Steelers and the Saints. He saw action in one game with the Panthers and fumbled his only carry.