ATLANTA -- Georgia Tech fired defensive coordinator Al Groh on Monday, hoping a change will save what has been a hugely disappointing season.

Coach Paul Johnson announced the move two days after the Yellow Jackets (2-4, 1-3 Atlantic Coast Conference) lost 47-31 to No. 16 Clemson, their third straight defeat -- all of them while surrendering more than 40 points, the first time that's happened in school history. The stretch included an embarrassing 49-28 home loss to Middle Tennessee.

Johnson has never fired an assistant during the season, but felt he had to do something to show he was committed to turning things around. The Yellow Jackets are off this week, giving them extra time to adjust to the jarring change.

"To me, it was inevitable," Johnson said. "I didn't want to give up on the rest of the season. I still think we can come back and have a good season. That's why I did it now."

The Yellow Jackets have one of the nation's worst-ranked defenses -- 89th in points allowed (30.2), 90th in total defense (431 yards per game) and 103rd in third-down efficiency. That latter figure might be most troubling to Johnson, whose team has allowed opponents to convert nearly 48 percent in those situations and was especially poor against Clemson. The Tigers were 13 of 19 on third down, keeping Georgia Tech's potent offense on the sideline.

The defense has been especially leaky in the second half, squandering a 17-point lead to Miami and allowing Virginia Tech to kick a tying field goal after going ahead of the Hokies with less than a minute remaining. Both times, the Yellow Jackets lost in overtime.

Groh, a former head coach at Virginia and for one season with the NFL's New York Jets, was in his third year running Georgia Tech's defense. He issued a statement through Georgia Tech saying he understood the decision. The 68-year-old Groh also thanked the players and his assistants for their hard work.

"The institute has decided to go in a different direction, which I respect," Groh said. "I aimed to give the best that I had every day. It's been an honor to be a part of the legacy of Georgia Tech football. I feel positive that this is a good time in life to move on to a new situation."

The time to move on has been building for a while.

Johnson's discontent with Groh actually goes back to last season, when the Yellow Jackets lost five of their last seven games, capped by a 30-27 overtime loss to Utah in the Sun Bowl. The Utes scored two fourth-quarter touchdowns to tie the game, then won in overtime.

This year, more of the same.

"I was hopeful as we started, this being the third year. I was hopeful we would see some improvement," Johnson said. "I was encouraged at the first of year, but it became apparent that was short-lived. The last three games was a carry-over of the last six games a year ago."

Secondary coach Charles Kelly will take over as interim coordinator, and Johnson shook up the rest of the defensive staff. Specials teams coordinator David Walkosky will oversee the line, Andy McCollum shifts from the line to inside linebackers, and Joe Speed moves from inside to outside linebackers.

Their orders are clear.

"My big goal is to simplify and see if we can't get lined up and play faster, play harder," Johnson said. "I don't think you've got to trick people. You've got to line up and know what you're doing and play fast."

Groh installed the 3-4 when he got to Georgia Tech, but it was clear the players never fully picked up the scheme. Also, there was a difference in philosophy with Johnson, who felt Groh didn't do enough full-speed work in practice.

"To me, defense is energy and playing fast and playing with enthusiasm," Johnson said. "It's hard to get that if you don't go live (full-speed drills) some of the time."

While Johnson's focus has been on running the option offense, he believes the Yellow Jackets have plenty of talent on the defensive side.

"I'm not sold that we don't have good players," he said. "I'm very confident in our players' ability. We'll see."

Johnson praised Groh's defensive knowledge, but said he was never able to pass it on to his players.

"Al is a very smart man. He understands what's inside his head," Johnson said. "The problem is we weren't seeing it on the field. For whatever reason, it wasn't transcending."

That left the head coach with only one option -- make a change.

"It's really disappointing and frustrating," Johnson said. "You never want to do it. But, to me, that's part of being a leader. Sometimes you have to do hard things. I still have a great deal of respect for Al. In my mind, he's had a very good career. Maybe he will still coach. I don't know what the future holds. It just wasn't working here."