ATLANTA — Justin Thomas opened Georgia Tech's spring practice on Monday with an important vote of confidence from coach Paul Johnson.
    Thomas is one of four quarterbacks competing to replace 2013 starter Vad Lee, who transferred to James Madison. Thomas was Lee's top backup and Johnson said that makes him the player to beat in the competition.
    "He's played the most," said Johnson of Thomas. "I would expect him to be a hard guy to beat out."
    Lee started every game as a sophomore as the Yellow Jackets finished 7-6 last season. Thomas played behind Lee in 10 games and made his biggest impact as a runner in Georgia Tech's spread-option offense.
    Thomas completed only 9 of 17 passes for 131 yards with one touchdown and two interceptions as a freshman last season. Tim Byerly sat out the 2012 season after transferring from Middle Tennessee State and appeared in four games last season, rushing for 119 yards and two touchdowns.
    Two freshmen, Ty Griffin and 2014 early enrollee Matthew Jordan, are behind Thomas and Byerly on the depth chart.
    When asked about the learning curve for the freshmen, Johnson's answer said a lot about the edge in experience for Thomas and Byerly.
    "A guy like Ty Griffin, it's like drinking from a fire hose," Johnson said, referring to the difficulty to keep up with the constant flow of new plays.
    Thomas could be a dangerous running threat as a starter in the option attack. He looks smaller than his listed size (5-11, 185) but he has good speed and could be difficult to bring down when he turns the corner.
    Thomas ran for 234 yards in 2013, averaging 7.1 yards per carry.
    "I'm trying to show I can be a leader and I can go out there and take charge," Thomas said.
    He said "there's no pressure" to opening spring as the top quarterback.
    "I'm not trying to think of it that way, just going in every day working hard," Thomas said.
    Lee's decision to transfer was a surprise to many following his first season as a starter.
    "I had a very good relationship with Vad," Byerly said. "We were always cutting up. It was kind of a bittersweet moment. I knew as one man goes another man has to step up. .... At the end of the day there's an opportunity at hand and I hope to take advantage of it."
    Georgia Tech must replace its top three rushers — Lee and running backs David Sims and Robert Godhigh. The Yellow Jackets also lose three starters from the offensive and defensive lines.
    A player to watch is freshman Travis Custis, who was a highly rated recruit in 2013 but had to sit out last season to meet NCAA eligibility requirements. Custis is from the same Lovejoy High School near Atlanta that also produced former Georgia Tech running back Tashard Choice.
    Custis (6-0, 207) broke many of Choice's school records.
    "He's just a really good athlete," said Johnson of Custis. "He was a great high school player. He's quick and fast and we're hopeful he can transition really quick and give us some help there. We're certainly going to give him a look."
    Zach Laskey is Georgia Tech's leading returning rusher.
    The Yellow Jackets also lose three starters from the offensive and defensive lines.
    NFL scouts will be on campus on Friday for Georgia Tech's pro day. The top attraction — and perhaps the player who will be most difficult to replace in 2014 — could be defensive end Jeremiah Attaochu, the school's all-time leader with 31 ½ sacks, including 12 ½ last season.