To echo Payton Menning sentiments here, it seems Tarik is thinking about retirement, but hasn't made his decision yet. Dungy spoke about the subject on Colts.com today:
Dungy, entering his sixth season as the Colts' head coach, said he has spoken with offensive tackle Tarik Glenn regarding the recent published reports that the three-time Pro Bowl selection is considering retirement.
Between waiting for this and waiting to see if Corey Simon will show up to Training Camp, I might have a coronary.
"He told me he is considering it, and he wanted to think it through and talk it through," Dungy said. "We talked about some of the issues, and we'll see what happens."
Update [2007-7-23 20:28:37 by BigBlueShoe]:Per PFT: On NFL Total Access, Adam Schefter reported that Polian and Dungy think Glenn could come back for one more season. We shall see.