After solid performances in the first two preseason games, the Saints tackled terrible in the first half against Jacksonville last Friday. The Jaguars opened with an 80-yard touchdown drive and moved 68 yards for a touchdown on their third series, slipping tackles right and left on both possessions.

Interim Saints coach Joe Vitt made better tackling the No. 1 practice priority Monday and Tuesday, with the team going in full pads.

“It was the main emphasis two days in a row,” Vitt said. “Main emphasis. Proper angles to the ball, proper fits, their eyes open and they had to wrap up.”

New defensive coordinator Steve Spagnuolo completed the installation of his scheme last week. Incomplete tackling made it appear as if the Saints were playing in it for the first time on Friday.  

“It wasn’t very good, and the guys recognize that,” Spagnuolo said. “The guys talked about it, but talking about it doesn’t do anything. This group needs to respond now, and when they’ve got something to prove, they usually respond. We’ll see what happens (against the Houston Texans this Saturday).”

Another MLB injury: The Saints lost a third middle linebacker in practice this week after losing two in the game against Jacksonville. Vitt said Wednesday Ramon Humber will be out about 10 days with a hamstring injury, joining starter Curtis Lofton (high ankle sprain) and backup Chris Chamberlain (season-ending ACL tear) on the sideline.

“You got a ticket?” Vitt responded when asked who would play in the middle against the Texans. “You’ll see.”

Vitt said Barrett Ruud, whom the Saints traded for on Monday, likely would not play this Saturday after practicing for the first time on Wednesday. Earlier this week, Vitt said undrafted free agent Lawrence Wilson would get a long look at middle linebacker.

Vitt added Lofton, who likely will sit out the rest of the preseason, would be available to play immediately if the regular season started Wednesday.

Praise for rookie CB: After struggling in the first week of camp, fifth-round draft pick CB Corey White has come on. The low point may have come on draft night when he said he was waiting to intercept a pass from QB Drew Brees in practice. That line has made him fodder for ribbing ever since.

“He’s a good player with a real bright future,” Vitt said. “What he’s done a good job of since he was drafted is keeping his mouth shut because he hasn’t touched one of Drew’s balls yet. We think he’s going to be a real good player. He’s fast. He’s quick. He’s done a good job of retaining the defense. He has a lot of confidence. He’s improved.”

This and that: Vitt said RB Darren Sproles (sore knee), who returned to practice on a limited basis this week, would be held out Saturday as the Saints try to get him back to 100 percent for the start of the regular season. … Special teams coach Greg McMahon said the competition between kickers Garrett Hartley and John Kasay would last through the fifth and final game of the preseason.

Follow Saints reporter Guerry Smith on twitter @CBSSportsNFLNO.