I see Tejada as a marginal upgrade on the bench. Don't get me wrong, I think Tejada will be usefull and may help the Padres win an extra game or two. In the final 62 games this year I see the Padres using him as follows:
5 games starting at 3B with Chase out of the lineup
5-10 games starting at 3B with Chase in LF
10 games starting at shortstop
Maybe a couple games in LF or 2B
Mostly, as a pinch hitter.
They will most likely remove Tejada in close games where the Padres have the lead for defensive purposes.
I hope the Padres get a clue and cut Stairs now that the Padres have added to their bench.