I Don't Get It

Jay Gibbons has played 90 games in his career at 1st Base. He's played 26 games in left field. So why is the Sun referring to his "experiment at 1st Base" being over? Why does he have to "concentrate more on left field?" The terminology Jeff Zrebiec uses is weird.

This is not like moving Javy Lopez to 1st Base last year, with Lopez having played 2 innings at 1st his entire life? Why does Gibbons know have to relearn the position, and why is it an "experiment?"