The pair join a team with a defense led by last year's top pick Mario Williams, whose development will be key in Houston's success after a disappointing rookie season.
Players and coaches alike believe the highly touted backup can be the leader the team needs but never had in Carr, who was dumped after the Texans posted their fifth straight losing record in 2006.
"I've been impressed with the way he handles himself," coach Gary Kubiak said. "That's a lot to handle. You go and make a trade like that for a kid and the pressure to come in here and take over this football team is great, but he's handled himself tremendously this offseason. He's been a great worker, very confident kid about his opportunity and what he's fixing to go take on."
Despite finishing 6-10 last season, the Texans have something to build on after winning their final two games for the first back-to-back victories since 2004. One of those was a morale-building Christmas Eve win over AFC South foe Indianapolis, the first in franchise history.
Schaub has been learning Kubiak's offense since he was traded to the Texans in March, and his transition to the team will be aided by the rapport he's established with Johnson. Houston's top offensive threat caught a career-high 103 passes for 1,147 yards last season.
Kubiak is a big fan of his, despite the 25-year-old amassing just 456 yards receiving in four seasons.
"It's a concern of mine because we're so young after Andre," Kubiak said. "We're going to find out if we have a couple of young players that are going to step up and be big time pros. I'm going to give them the opportunity to do that."
Though probably past his prime, Green reinforces a running game that sputtered last season until December while relying on inexperienced and injured backs. The Texans were forced to start rookie sixth-round pick Wali Lundy after Domanick Williams (formerly Davis) was placed on the injured reserve just days before the season.
Ron Dayne finally got healthy and became a factor in December, rushing for 429 yards and five touchdowns in that month alone.
With the one-two punch of Green and Dayne, the Texans are in much better shape at the position than they were entering last season.
"I think we have big play potential with number 30 (Green) back there," Kubiak said. "If we are right in the run game and we catch him right, we have a chance for some big, big plays. If we can run the ball that way, we can get people off Andre."
Of course, as usual, questions abound when it comes to who will protect the new quarterback after Carr was sacked 249 times in five seasons. The Texans thought they'd found their left tackle of the future in second-year player Charles Spencer, but a broken leg just two games into last season has left doubt about if the 351-pound player will ever play again.
If Spencer can't go, the Texans will rely on 10-year veteran Ephraim Salaam or former Kansas City player Jordan Black to protect Schaub's blind side.
Williams, the shocking No. 1 pick last year, will need to show much more than he did in his rookie season when he finished with 47 tackles and 4 1/2 sacks.
There's several reasons to believe he will.
The defensive end has recovered from plantar fasciitis in his right foot that slowed him for most of last season. He also seems more relaxed a year removed from the constant Reggie Bush/Vince Young questions and, perhaps most importantly, he's got help on the line in this year's first-round pick Amobi Okoye.
Along with taking pressure of Williams, the Texans hope Okoye, the 20-year-old defensive tackle, will beef up their paltry pass rush. Houston was 27th in the NFL in sacks last season.
"I look at him and I said: 'This kid would have gotten there many times last year,"' Kubiak said. "I think he's going to give us an added pass rush ability inside and make people pay attention to more than one guy when it comes to turning protections and stuff like that. Hopefully that will free up other players to make plays."
Another Texans defender, who unlike Williams, far exceeded expectations as a rookie, was linebacker DeMeco Ryans. The former Alabama standout and second-round draft pick earned defensive rookie of the year honors by leading the league in solo tackles with 126. His 156 total tackles were the most by a rookie in the last 20 years, and he had 3 1/2 sacks.
But he won't get to coast on his rookie accomplishments. Kubiak is expecting even more from Ryans this season.
"The year he had was tremendous," Kubiak said. "Hopefully there's many more years like that one to come. I think he improves just through the knowledge of the game. He's a quiet guy who does his job and gets everybody in the right spot. Never a word out of his mouth and what a leader for such a young kid, but I think the kid's knowledge of the National Football League is what is going to get him to the next step."