DETROIT -- John Smoltz will make the first of two Pawtucket rehab starts on Friday night, and he hopes to make his debut with the major-league club after the two outings are complete.

Smoltz, who is recovering from shoulder surgery, expects to throw 90 pitches or six innings for the PawSox Friday at home against the Louisville Bats. His second start would probably come the next Thursday, in a road doubleheader against Syracuse.

That would put the 42-year-old hurler in line to pitch June 16 in Fenway against the Florida Marlins, but nothing is set in stone as yet.

"Nothing is concrete right now and that's the best way to approach it, because as I explained, I can only really concern myself with Friday," he said. "Get myself in the best possible shape for Friday, move on, and keep doing the same thing. There's going to come a time when I'm going to stop visiting these other cities, and I'll be pretty grateful for it. Though it's been a pretty neat experience so far."

That said, Smoltz hopes he can make his major league return after those two starts are done.

"I hope so. Sounds a little bit like a broken record, but when I got with this organization it was going to be a timetable that was suitable for them, and I'm honored to be part of whatever it is," he said.

The organization's timetable is affected by its full major-league rotation. Brad Penny is probably the most likely candidate to lose a spot when Smoltz returns, but it's not clear what Boston would like to do with him. Penny cannot be traded without his consent until June 15, but he might accept a trade before that if the situation is favorable.

Sox manager Terry Francona had a conversation with Smoltz where they talked about possible return dates and the overall situation impacting his return.

"Again, we're getting closer to him being to the point where he would pitch for us," Francona said.

But Francona told Smoltz that the club itself isn't crystal clear on the exact return date or the steps that must be taken to make it happen.

"The one thing we kind of explained is we can't tell him someting we don't know but that we're thrilled with his progress and we'll make it work," Francona said.

Smoltz traveled with the team to his hometown of Detroit this week. He is coming off a successful rehab start for Single-A Greenville, where he allowed one run in five innings, striking out six.

"The last rehab start went really well. Dealing with the old normal 42-year-old achy back. A combination of my travels and my crazy schedule. But I accomplished everything I wanted to accomplish on the mound," Smoltz said. "It was the most productive outing I've had."

dbarbari@projo.com