By Neil McLeman Mikel Arteta is ready to unleash his “very powerful midfield” combination of Declan Rice and Thomas Partey together for the first time in the Premier League on Monday night. The Ghana star started the league season playing at right-back and has played only 15 minutes since August after a spate of muscle injuries. But the Gunners boss is delighted the £45m signing is finally fit to return to the squad and make an “impact” starting at Sheffield United tonight. And the potential pairing with Rice, who joined the club last summer, can add a new dimension to Arsenal for the title ru…