Thornton had an MRI on his forearm last week that cleared him for more intensive work.
"I am looking forward to getting some game situations work in," Thornton said Friday.
Thornton was used to excess last season, partially because of his effectiveness and durability, pitching in a career-high 74 games.
"I am 36, so there will be some attrition after throwing as much as I have," Thornton said. "Honestly, I still throw 95 mph so I have been blessed with that."
Thornton lost 20 pounds in the offseason after finding out he had allergies to dairy and gluten.
"I went through a battery of tests and found out these foods were causing me to retain water and adding congestion," Thornton said. "I didn't mean to lose the weight but it all came off after I changed my diet."
"We have some people who can get the job done these days," he said. "I think they can spread it out a little bit now."
Thornton has been his team's only reliable bullpen answer from the left side since joining the Sox in 2006. Thornton holds the record for appearances by a White Sox pitcher (472, also the most in the American League since 2006) and is the all-time holds leader (146).
The wear-and-tear factor is the major concern for Thornton.
"I will always take the ball from them," he said. "That is what we do in the 'pen, but a little less work with the talent we have would be OK."
Although Thornton lost 10 games in relief last year, he set a career high in holds with 26.