Days before pitchers and catchers were due to report to Mesa, the Oakland A’s roster was anemic. Not decimated — the talent and core from past contending seasons remained. But the A’s didn’t have a counter punch as other teams purged its overflowing bin of free agents. They seemed resigned to start retreating out of contention. But through a flurry of moves in the final hours, the A’s sent a bat signal that they weren’t sitting on their hinders. They could make a better team, despite the extreme budgetary confines. That’s what sealed the deal for Trevor Rosenthal, who ultimately sign a one-yea…
