This move is not a surprising, considering Diehl's play last year and the release of Rich Seubert. Still, some people will be very concerned about playing the unproven youngster Beatty at the most important position on the line. Those are legitimate concerns, but I believe it's time to let Beatty sink or swim, unless the Giants are going to bring in another tackle.
Worst case scenario: Beatty fails and the Giants move Diehl back to tackle, where he is capable but below average. Best case scenario: Diehl is a beast as an interior lineman, and Beatty finally fulfills his potential.