Kovalev (pre Ward) dominates him to a wide decision. People really sleep on the fact that power aside, Kovalev is a very, very good boxer puncher. He just so happens to have dynamite in his fists. Kovalev could box with damn near anyone. He won't stop Froch, Froch is a stud and would take his lumps, but he'd see the final bell.
As a big fan of both fighters let's be honest here. Froch was 37 or 38 in that fight. Kovalev started to decline when he was 33. And by the time he was 35 he was a shell of himself. By the time hes 37 he will probably be nothing remotely similar to what he was. So I dont think that's a truly accurate comparison to make. Prime for prime I would favor Kovalev. Froch would make a late charge due to his massive stamina advantage. But he wouldnt be able to climb out of the scorecards hole.
Prime Kovalev ie. the one who absolutely annihilated the teak-tough Cleverly, and Campillo, Sillakh, Lionell Thompson etc. was an absolute monster and he would administer a frightful beating to Froch and as tough as Froch was albeit it was never proven above 168, would KHTFO. Froch was dropped and nearly KO'd by Groves, dropped by Jermain Taylor, hurt numerous times by Kessler including Kessler making his legs dip, Charles Adamu made Froch's legs dip too. Hurt a bit by Dirrell. And Dale Westerman rocked him a few times. Don't get me wrong, Froch was teak-tough. However, he was always too easy to hit and an absolute prime Kovalev (pre-B-Hop) hit extremely hard and was absolutely relentless.
I can honestly see why he "just fancies it". 1) He's Carl Froch, his ego knows no bounds. 2) He's a mentally tough fighter with great body shots and very good stamina, we know for a fact that these attributes can be Kovalev's kryptonite. But if Groves can find Carl so easily and drop him with little more than a 1-2, a prime Kov would decimate him with his spearing straight punches. Froch just doesn't have the defense for his own strengths to come to the fore. Kovalev within 6.