Linebacker Sean Weatherspoon's season-ending Achilles injury will test that belief.
Atlanta lost one of its defensive leaders on Tuesday when Weatherspoon tore his Achilles tendon.
Smith is confident the Falcons have improved depth at linebacker and better size on the defensive line as they appear headed for a 3-4 base scheme. The team drafted four linebackers last month.
Among the rookies who now have an increased opportunity are Notre Dame's Prince Shembo, a fourth-round pick, and Syracuse's Marquis Spruill, a fifth-rounder.
Smith said this week he is impressed with the continued progress of two 2013 undrafted rookie linebackers, Joplo Bartu and Paul Worrilow. Worrilow led the team in tackles and Bartu was third, but still the defensive problems helped lead to the disappointing 4-12 finish. Veteran linebacker Akeem Dent is another option.
''They are a much more mature group,'' Smith said. ''We went through some growing pains with them last year that are going to pay dividends moving forward.''
Smith said additions to the defensive line also should give the linebackers better protection to make plays. They signed defensive end Tyson Jackson and defensive tackle Paul Soliai in free agency and drafted defensive end Ra'Shede Hageman in the second round.
''Those guys are big guys and will be able to anchor the defensive line and that's what we need,'' Smith said. ''We've got to stop the ball from getting to the second level.''
Weatherspoon is expected to make a full recovery following surgery.
Though the loss of Weatherspoon was devastating, training camp is still one month away. The Falcons have time to adjust their plans, unlike last season, when Weatherspoon hurt his foot in Week 2 and landed on the temporary inactive list. He returned in November but then hurt his knee late in the season.
He was still rehabbing the knee when running under the supervision of the team's medical staff on Tuesday.
Injuries were a big reason Atlanta's streak of five straight winning seasons came to a crashing end last year. The Falcons closed the disappointing season with 11 players on injured reserve, including such prominent players as wide receiver Julio Jones and offensive tackle Sam Baker.
On Tuesday, Smith firmly said he was through talking about last season's bad news.
''Last year was last year and we try not to talk about it anymore,'' Smith said. ''When you have your best players on the field, it really helps.''
Hours later the team announced that Weatherspoon, regarded as perhaps the team's top defensive player, was lost for the year.
Weatherspoon set career highs with 80 tackles, four sacks, 14 tackles for losses and eight pass deflections in 2011, the only year he has played 16 games.
Though he had been held out of organized team activities this month, Weatherspoon was expected to be cleared for training camp before his latest injury.
NOTE: The Falcons waived tight end Andrew Szczerba and punter Matt Yoklic. Szczerba was signed to the practice squad on Nov. 13, 2012 and spent the 2013 season on injured reserve. Yoklic, from Pittsburgh, was signed as a college free agent on May 12.
AP NFL website: www.pro32.ap.org and www.twitter.com/AP-NFL