When PayPal announced that its relationship with Discover had been turned on this week, Don Kingsborough, head of retail at PayPal, said the company expected to be in 2 million retail locations by the end of this year. That seemed a bold prediction considering they were in only 250,000 when the news was announced. Turns out they probably knew something was coming up.

Today, PayPal partner Discover announced contracts with 50 merchant acquirers, extending in-store acceptance of PayPal to — you guessed it — more than 2 million merchant outlets by the end of 2013.

"With the signing of 50 merchant acquirers to date, we are well on our way toward helping PayPal reach its goals of acceptance at millions of physical locations in the U.S.," said Diane Offereins, president of payment services at Discover. "Our relationship represents the unique abilities we have to leverage our payments assets and infrastructure to work with emerging payments leaders like PayPal, and we’re proud of the progress we’ve made in such a short time."

With the relationships, PayPal accountholders, who number more than 55 million in the U.S., can pay with their PayPal account at the point of sale at retail stores, restaurants and gas pumps. Accountholders need only enter the mobile number associated with their PayPal account on the POS keypad — along with a PIN — to make a purchase.

Acquirers who have committed to the effort include Heartland Payment Systems, TSYS, WorldPay and Vantiv.

Read more about retail and mobile payments.