"We have to test the knee and the quad in a game environment," Reds manager Bryan Price said. "Joey has run the bases. He's taken ground balls. He's taken batting practice. I think he needs to play in a game -- somewhere in the neighborhood of five or six innings -- and see how he holds up. That's one thing we haven't been able to replicate over the course of his rehab."
The club is treating the rehab games as a day-to-day plan without setting a length on the number of games. The Bats are in Pawtucket through Tuesday before returning to Louisville for a series on Wednesday.
"It's one and we'll see," Price said. "If he'll play one game or five games, we don't know. But we are going to evaluate after every game and see where we are. Certainly, we'd like to have him back with the club, but we've made an investment to get him healthier, closer to looking like the Joey Votto we know."
Votto hasn't played for Cincinnati since May 15 and went on the disabled list six days later.
There is no one specific test that Votto has to pass while playing in game conditions. The team would like to get a sense on whether Votto can play on an everyday basis and if he might need periodic off-days to keep his leg strong.
"It's really just the durability of being in a game and doing everything," Price said. "If you're playing first base and have to make a quick first step on a ground ball or break quickly to cover first base; getting out of the box on a swing which is something he hasn't done in a while and the rigors of getting up and getting down -- being hot, being cold, sitting on the bench and back up, seeing how that progresses."
Mark Sheldon is a reporter for MLB.com. Read his blog, Mark My Word, and follow him on Twitter @m_sheldon. This story was not subject to the approval of Major League Baseball or its clubs.