He won't, but he might be quite good.
Allen appears to be a lot like Chris Carter, only he can play some defense and his trials in the big leagues have not reminded people of a laid-back deer going, "Hey, headlights ... cool, man." In this morning's SF Chronicle, Billy Beane is cited as indicating that Allen will report to Sacramento but will be in the big leagues "very soon". Allen is a 1Bman that Beane notes can also play in the COF, bringing up the question of where Allen will play in Oakland and whose job he will take.
First of all, I believe the writing is on the wall that Daric Barton's future with Oakland is about as bright as most players' who spar with the team through the press. In the one week since Barton made disparaging claims about the A's medical staff and Beane rebutted sharply that Barton had not cooperated with trainers' attempts to help him, the A's have tried to acquire 1Bman Lars Anderson and then acquired Allen, whose primary position is 1B.
Coincidence? Partly. It was trading deadline week and whatever the reason Barton has had a terrible season that calls into question how set the A's are at 1B going forward. But nothing gets you out of Oakland faster than attacking the team through the press.
Meanwhile, COF is starting to look a little better each day with Willingham reiterating his openness to staying in Oakland beyond 2012 and Michael Taylor finally reverting back close to his form of 2-3 years ago. However, Willingham may or may not return and even if he does his best position right now -- and most certainly going forward into his mid-30s -- is DH.
The same is true of Chris Carter and then some. The A's may finally have come to terms with the fact that Carter may or may not be able to mash big league pitching, but he most certainly can't field it anywhere. Carter's only position is DH, and he has struggled enough with the "H" part that his status even there is uncertain.
So here's one formula the A's could follow. They could try to re-sign both Willingham and Coco Crisp, letting David DeJesus go, but slide Willingham into DH duty a lot of the time. They could put Allen at 1B, bring up Taylor, keep Carter at AAA to prove himself and slide in at DH when ready, and roll with this lineup out of spring training:
Weeks - 2B
Crisp - CF
Allen - 1B
Willingham - DH
Sweeney - RF
Taylor - LF
Sizemore - 3B
Suzuki - C
Pennington - SS
Against LHPs, Willingham moves to LF with Sweeney on the bench to come in for late inning defense, and a guy who can hit LHPs well moves into the DH slot. Perhaps that's Conor Jackson, perhaps it's Carter at some point, perhaps it's a "Marcus Thames" type (also known as "the Bobby Kielty role") that is part of your bench.
If Taylor busts but Carter rakes, you have the chance to play Wilingham in LF full time, call up and DH Carter, so at least there are fallback options. Basically, you need one of Taylor or Carter to be good, but not both -- though Taylor busting does mean more Willingham in the OF.
Anyway, just throwing it out there to suggest that the above lineup doesn't look too bad. It would, of course, look better behind Gio, Cahill, and Brett Anderson, but that's for another time. The point is: Brandon Allen shall save our franchise. Especially if the other 24 guys are really good.