20-year-old phenom, Justin Upton, looked ready to have a breakout season at the beginning of the year, batting .327 with 5 HR & 15 RBI in April, for the MLB-leading D-Backs. Then came May. Through 5/5, his batting average was up to .348, but by the end of May, his average had dropped to .275. As of 6/25, his average stands at .240. June has been his worst month yet, going 6-for-53 at the plate (.113).
His 06 Bowman Chrome Auto RC averaged an amazing $196.74 TAC in April. That average dropped to $136.35 in May, and can now be found in the $120's range. His 06 Bowman Chrome Ref Auto #'d 500 dropped from $256.10 in April, down to $176.50 in May, and more recently has been selling for around $150-160 TAC. If you don't want to spend $100+ for his Auto rookie, a good alternative is his 06 Bowman Sterling Auto RC, which has been selling in the $55-65 TAC range this month.
Coincidentally, his team's record went south around the same time that his bat started to give out. They were 20-8 in April, and 20-31 in May-June (thru 6/25). Fortunately for Arizona, the rest of the NL West has played even worse than they have, allowing them to maintain their top spot.
I think that it's pretty clear that Upton is going to be a hot commodity for years to come. It'll just be a matter of when he can gain enough consistency at the plate to help this young D-backs team win. If he continues at this current pace, there should be some great buying opportunities to be found on auction.