Tarkowski replaced Keane at Burnley, Keane kept him out the side for the 12 month they were in the same squad. Keane and Ben Mee were the starting C/B in Keane's last season.
Personally not so convinced he wouldn't bring Red Con or even Mina back in if he felt it was going to make a significant difference. Think the defence would be acceptable if there was any sort of threat going forwards as teams would approach the games differently, as it stands its like every team we play already has the crucial 'first goal' advantage.