My guess is a mild "maintenance" cycle
3g of test per week
GH (if he can get it it)
some clen before any shirt removing appearances, e.g recent posing in Dubai
I once asked what sort of gear Lou Ferrigno runs to maintain his size - and he is huge given that he just turned 66 last month. Given his age, he is a large man, even if he is nowhere near as big as he was in his prime. Someone replied that Lou likely runs about a gram of testosterone a week for maintenance. That seemed HUGE to me, but I suppose for top level bodybuilders, that is hardly anything. So it is quite possible that Jay runs more than that. At the same time, at Jay's current age [44], it is probably not hard for him to maintain a higher level of body mass. The issue is most likely keeping his body fat low. That would be hard to do, and something I have maybe found a touch more difficult to do ever since turning 35 [I turned 36 seven days ago]. That said, I have not trained at all since April 1st - a long time, I know, but I will start again next week and be ready for the 2018 stronger season by May 1st, no problems at all.

Even faster if I ran gear, but I can't really do that if I expect to compete at 170. I am currently 185-lb in clothes, so I am likely 183 naked, as opposed to 173 naked. I would probably be 178 if I trained, so I probably have 5-lb of body fat more than I normally do...but that's not so bad for 36 years old, and just starting to see my metabolism slow down.
Relating that to Cutler - and this is just a guess - but I assume maintaining muscle mass is not overly hard for him, but staying lean is. So maybe he does use three grams of testosterone a week, or perhaps he is closer to the gram allegedly used by Lou [according to the speculations of one Getbigger]. As with any aging male, maintaining body weight is probably not difficult for him - even muscle mass. But cutting body fat is another matter entirely, and likely something he has some "help" for.
That said, Jay still has some commercial interest in bodybuilding, so he probably wants to have a slightly bigger body than just a bit of muscle, in order to still sell himself in the industry. It is also not likely overly difficult for him to be extremely muscular, albeit not his competitive off-season 315-lb at 5'8.5" that he historically was. Nor is that size good for his health! In a 2002 Ironman article [I believe] he told Lonnie Teper that he wanted to retire at 32, and slim down to around 230-lb. I remember thinking that, Jay being my height, 230-lb would be HUGE! That was not taking into consideration a higher body fat percentage though, perhaps something closer to 18%. But still, that would be big. I think Jay's success in bodybuilding made him keep going for a lot longer than he wanted to, and whatever health goals he once had, he decided were worth trading in for success in bodybuilding, which he obviously had plenty of.
I can't know what Jay currently uses. But 1-3 grams of testosterone a week [maybe as low as one gram] is likely, as the OP said. I do want to add one thing: three grams seems a bit steep though, does it not? Wouldn't one gram a week coupled with some GH be plenty to maintain his current size? After all, it's not like he is in competition shape anymore.