I simply stated that IF he gets 550 AB from the 9-hole, I believe he'll score 100 runs. You're trying to pull data from here and there, and that's fine. If he gets just 500 ABs and they're all from the 9-hole, I believe (as I said before) he will threaten 100 runs. He bats 9th...he'll have the top of a very potent lineup coming up behind him. And with as potent as the Rangers lineup is, I think it's very possible the 9-hole for the Rangers gets 625+ PAs.
According to Fangraphs, the average 9-hole gets 610 PAs in a 162-game season. Let's say Deshields plays 150 games, all hitting from the 9-hole. According to Fangraphs average, that's 565 PAs...but then the Rangers aren't an average lineup. So maybe we could assume as many as 580 PAs...possibly more. In his career, Deshields has walked once for every 10 PAs...that's 58 walks, so let's round up to 60. That gives him potentially 520 ABs from the 9-hole with that lineup coming up behind him. Do you agree that him getting 520 ABs from the 9-hole is virtually the same as getting 520 ABs from the leadoff spot? If Deshields, thanks to the strength of the Rangers lineup, simply maintained his career average of scoring a run every 5.06 ABs...that alone would give 103 runs in 520 ABs. Or, he scores once ever 5.85 PAs...in 580 PAs, that would come to 99 runs.
That said, runs are dependent on the guys behind you moving you around and bringing you in, but the fact is that has happened at a high rate for Deshields as a Ranger. I'm not guaranteeing Deshields scoring 100 runs...but I do like his chances if he plays 150 games this year and hits either leadoff or in the 9-hole.