The euro hit a nine-year low against the dollar on Wednesday, falling as low as $1.18. Weaker growth and falling prices in the euro zone have led to wide speculation that the European Central Bank could ease policy.
Read MoreEuro zone deflation: Why it matters
With the Fed potentially raising interest rates as the euro zone eases, the dollar could bulk up even more, Doll said.
But the Fed could help send the dollar lower against the euro. If Fed board members signal concern for the dollar in the near future, they could "talk the dollar down," said Larry McDonald, senior director at Newedge USA.
"If the Fed mentions the dollar as a concern, there's so much pent-up bullishness it could create a reversal," McDonald told "Closing Bell."
Read MoreEuro slide could take it to parity with dollar
Easing in Europe could also send the dollar lower against the Euro, CNBC "Fast Money" trader Brian Kelly said on "Closing Bell." If Europe eases monetary policy and investors begin to rush in, dollars will be sold to buy into the euro, he said.
Even with the potential shift, Kelly sees the dollar rallying for the second half of 2015.