The former German goalkeeper joined the FA Cup winners for the third time after two spells between the sticks for Arsene Wenger.
Lehmann has been drafted in to bolster the Arsenal backroom staff in a general coaching role to help with the first-team throughout the 2017-18 campaign.
The Gunners finished in fifth place in the Premier League table last season to miss out on a return to the Champions League.
Lehmann is no stranger to success after being part of Arsenal’s famous Invincibles team that won the Premier League title in 2003-04 without losing a game.
The former Arsenal goalkeeper lifted the FA Cup and the Community Shield during his first spell at the north London side.
Former Arsenal defender Groves is thrilled to see Lehmann return to the Gunners to join the coaching staff ahead of the new season.
“There’s no doubt there’s still work to be done, we need another two players at least – both first team players,” Groves told bwin.
“I think the most underrated signing this summer was adding Jens Lehmann to the coaching staff.
“He’s got a no nonsense character, he’s a winner and will certainly give the team a kick if they need it.”
Arsenal have signed Bosnian defender Sead Kolasinac in a free transfer from Bundesliga side Schalke 04 in the summer transfer window.
The Gunners spent a club record £52m fee on Lyon striker Alexandre Lacazette last month.
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