After playing 11 games for Lehigh Valley and hitting .283, Sizemore's contract was selected by the Phillies from the IronPigs on Friday.
Sizemore batted just .216 with a .612 OPS in 205 plate appearances for Boston before being released.
Physically, he said, he is feeling good but . . .
"It's one of those things where I am going to need a season or two just to kind of get my legs back underneath me," Sizemore said before Friday's game. "But every day I feel better, it's just a matter of getting that strength and timing back."
He was honest about his performance in Boston.
"I just didn't play well, just inconsistent," he said. "I think it is one of those things, if you are gone for a long time, you are going to have ups and downs."
Sizemore, who turns 32 next month, can play all three outfield positions. His most recent all-star season was 2008.
Among the procedures he has endured were left knee microfracture surgery, hernia surgery and surgery on his lower back and left elbow.
He says with all the physical setbacks, it is special to be back in the major leagues.
"Not knowing whether you will every play again, I think that every day I get to put a uniform on is something I appreciate," Sizemore said.
Lee to rehab Monday
Manager Ryne Sandberg said that Cliff Lee will make his next rehab start Monday in Florida in a Clearwater home game and will get up to 75 pitches. If all goes well, Sandberg said it's possible that Lee could make his first start for the Phillies next Saturday in Atlanta.
Lee, sidelined with a left-elbow strain, hasn't pitched since May 18.
"It is a possibility for him on Saturday but that is all yet to be seen, and [not] set in stone," Sandberg said.
Ruiz on the mend
Catcher Carlos Ruiz, who was placed on the DL on June 27 with a concussion, had his first day of baseball activity on Friday. He hit off a tee.
After the weekend Sandberg said Ruiz will head to Clearwater, Fla., to continue baseball activities.
"The plan is game situations somewhere right after the break," Sandberg said.
The all-star break for the Phillies is Monday through Thursday.