I didn't know where to put this so i decided to put it here, i think that Garp should be stronger than the admirals unless he's lost a hell of a lot of strength.
Reilegh was evenly battling Kizaru, and in his prime would most likely defeat the admiral. One thing i just dont believe is that when Garp was out cornering Roger and most likely fighting him, is that Roger just sent his first mate out to deal with him,i think Garp was able to take Reilegh, meaning he could beat and admiral (i personally think Garp was an admiral in the past).
And when garp said ive lost alot of strength in water 7, how literally can that be taken? I think it was just an excuse to allow luffy to leave but make it look like he was trying to capture him. I mean he could've just drawn for the hench iron ball straight away, it was only when luffy was disrespectful he lost it and actually tried to capture him.
Very since Oda took the space to add this little detail and does the same with Kizaru. Not crazy to imagine Garp was one of the Admirals in his day along with Sengoku and a third guy(Kizaru or maybe Dadan?). Who was he making an excuse for? He showed he didn't care what Aokiji thought, not that the Admiral cared anyway, and nobody else was around to listen besides some grunts. Comments like that seem to imply the strongest fighters are guys in their prime(Shanks, BB, Mihawk, Aokiji, etc.) and unlike other series older fighters do fall slightly behind. I'd consider Kizaru an older fighter since he seems more Sengoku's age than Aokiji's.