Short, who will be dual registered and so able to be called back for league action if required, has made a total of 18 appearances in his career for Warriors and scored two tries.
A product of the Warriors Academy and AASE scheme, Short has played eight games this season and featured twice in the Aviva Premiership.
The Worcester-born back joins fellow centre Sione Tu'ipulotu on going out on loan after the club confirmed the Tongan would move to Plymouth Albion for game time last week.
Head Coach Richard Hill said: "It's important that Andy gets games and we believe a spell at Cornish Pirates will be of great benefit to him.
"He remains a key member of the Worcester squad and we are excited about his future at Sixways. But we feel regular rugby, at a strong club like the Pirates who we have a strong relationship with, is crucial for him and his development."