"I'm close. I feel that I'm close," Prior said. "I feel right now more than anything it's just stamina. I felt good throwing. In the fifth inning I was a little bit tired, but I don't think I'm too far off."
So how many more rehab starts does that mean for the Cubs' starter?
"I don't know," Prior said.
"Right now I threw 60 pitches. I think they're going to want me somewhere up towards 90 before they put me in a game at [the Major League] level. If you figure going up 15 [pitches] at a time, it's kind of 1 1/2 [more starts] or in that in between stage. Obviously you want to increase the talent you're playing against too, so do I make a jump from here to Triple-A and make one or two starts there? That's not really up to me. That's up to them and what they hear and then once I get their input I'll give them my input."
Peoria manager Jody Davis thought Prior looked ready to move on.
"I think he looks ready for the next step," Davis said.
"[Kerry] Wood was a little more advanced [when he made a start for Peoria], but I thought Mark made a big step with what he did today."
Wood made one start for Peoria, one start for Triple-A Des Moines and then moved on to the Majors.
Prior not only saw his pitch count improve in his second start for Peoria, but results improved as well. He allowed just one earned run on three hits in front of a packed house at O'Brien Field.
On Monday Prior allowed three runs - two earned - on four hits in two innings of work.
Prior said he's accomplished both of his goals in his rehab starts thus far.
"The goal the other day was to throw strikes, get ahead of guys," Prior said. He threw 28 of his 44 pitches for strikes on Monday.
"The goal today was to find my breaking ball and I think I did that in the third inning. I was kind of able to find another gear in that third inning and get out of trouble, but today I really wanted to concentrate on throwing first pitch strikes."
Prior threw first pitch strikes to eight of the 18 batters he faced on Saturday. He threw 43 strikes and has not allowed a walk in his seven innings of rehab work.
"I was working ahead of guys. I only recall being behind two guys 2-0," Prior said. "Those are the types of things that you're working on. The things that make a lot of guys successful are the little intricacies in the game of pitching that sometimes we lose site of."
Prior's fastball topped out at 90 mph for the second straight game, but Prior said all of his pitches are coming along.
"I was happy with the way I threw the ball," Prior said. "The way my fastball was moving I had a lot of movement on the ball. My slurve was real good. My change-up was as good as it's been."
Prior said he will take a couple of days to see how he feels before deciding on the next step with his coaches.
Prior will join the Cubs in St. Louis on their current road trip, one he says will be crucial to the team.
"We're not out of it yet," Prior said. "Obviously I think this 10-day road trip against St. Louis, Cincinnati and Houston will tell a lot. You can find yourself around 7 or 8 [games back] and you're in a pretty good situation or you can find yourself 16 or 17 [games back]. They're off to a good start."