Ed Parker, head of EMEA ratings, told a conference: "Evidence suggests Turkey is on track for soft landing, there are encouraging trends in current account adjustments and import and export dynamics."
But he added: "We are concerned about the high level of current account deficit and external financing needs in the current global environment."
Official data showed on Friday that the current account deficit had widened to $6.1 billion in March from $4.2 billion a month earlier. However the first quarter deficit has fallen to $16.2 billion from $21.6 billion a year back.
The deficit last year was almost 10 percent of gross domestic product, among the highest in the world.
Parker, speaking at a banking conference organised by Mitsubishi-UFJ Securities, said global uncertainties would weigh on Turkey given its deficit, deleveraging by euro zone banks and the central bank's poor track record on inflation.
Annual price growth is running at 11 percent, data showed in April, more than double the central bank's 5 percent target for 2012. Economic growth is also expected to slow sharply from last year's 8.5 percent, with the IMF predicting 2.3 percent,
"If we see further progress on achieving a soft landing and see inflation heading to the central bank's target and see Turkey getting back to its potential growth rate then the chances of an upgrade will increase," Parker added.
Fitch rates Turkey BB+, just a notch under investment grade. Moody's and Standard & Poor's rate it a rung lower and S&P recently caused furore by cutting the country's sovereign rating outlook to stable from negative.
Parker indicated that Turkey's elevation to investment grade is unlikely to be very soon.
"Turkey has potential to get to investment grade within the next two to three years," he added.