Advice on asking for a LOR...

This topic came up on SDN, and I posted this question, but thought you all wouuld have better insight.
Maybe someone could offer advice on how to approach a former professor for a LOR:
I was working on a Ph.D. from 2001-2003. I ended up leaving the program because my major professor left for another university (that did not have a Ph.D. program - only Master’s level which I already have), and I decided to move back to my home state. Since my home state is IL, I applied to Northwestern to continue my Ph.D. there, and had a different professor than my major prof write me a LOR - I was his research assistant and we ended up publishing about 3 studies with the research I worked on. I was accepted to NW, but decided not to continue with my Ph.D. By then I had fully decided I wanted to go the medical route and not the research route. So, I’ve been working on my pre-reqs ever since.
My concern is approaching the professor that wrote my LOR for NW and asking him again to write one for med school, since he knows me in a research-related sense. I’m nervous about asking, mostly because I know how excited this guy was for me to get accepted to NW, and then I changed my mind - I feel like I might be a disappointment to him.
I thought maybe if I put it out there, someone would give me advice on how to approach him! Since I’ll need it by next year, I thought the sooner, the better to ask him.
So, any opinions?

Just tell him you saw the light and realized that only a loser would ever get a PhD in that area… a loser or someone who wanted to be a professor, which is the same difference in your opinion.

Seriously though, it sounds like this prof genuinely took interest in your desire to be doing what you wanted to be doing before, and likely nothing will have changed in that regard, if he sees that you are really excited about med school. You could always put a spin on it to the effect that “you feel you can do more research in the areas you think you can offer the most in, with an M.D. (or D.O.) behind you as well.” There are a lot of dual degree M.D./PhD programs, some of which are specific to research (check out UT San Antonio med school, as an example), so it doesn’t seem like that’s too far a stretch. If anything it seems like he should be happy you are pushing yourself farther to do more than you would have been otherwise with just a PhD program. I know there is some politics between PhD’s and M.D.'s, but I guess only you would know if that problem would exist with him.

Thanks, Sam.
I think that’s the reaction I’ll get, but I’m such a “people pleaser” that I worry sometimes for little things.
I guess the worst case is he would say “no”.
Would it be appropriate to e-mail him or call him? He is no longer at the university we were both at, and is actually at James Madison University now.

I’m such an email type of person that I assume everyone else is. I always prefer email for things like this because it gives me a chance to carefully “craft” the correct wording that will give all the right nuances of what it is I am asking for, etc.
With one exception (my D.O. who is a technophobe) I asked for all my LOR’s via email - granted some of them were from people I had nothing but email contact with really, anyway -and got amazing results. I guess that would be my personal choice, but if he is the type of person who hates (and rarely uses) email, then I guess a carefully “crafted” phone conversation would have to be the runner-up… all just my opinion of course. You may be more the type of person who just prefers talking with a voice than written words, as may he.
I’d do a “hi, long time no chat,” email starter, explaining what you’re doing and how excited you are at the potential research opportunities awaiting you as an M.D., etc., then tell him he was your mentor and you wouldn’t be where you were to make this decision if it weren’t for the things he taught you… and on that note… "how about another LOR?"
Just some ideas. Watch him post here now… “umm, hi, I think you’re referring to me in all these posts… and the answer is…”

He he! Yeah, he’s probably too busy to post here, plus medicine is not his interest - thankfully.
Thanks, Sam.
I’m going to wait a little while, but probably end up using Interfolio so I’ll have him work on it this summer/fall so I know it’s in the bank so to speak.