Treasury "capital injections" just result in greater payments to bank industry shareholders. Some of the ways it could work is that a bank receiving TARP money would buy back its shares (or buy, for cash, shares of competitors), use the Treasury funds to forestall raising new capital that (thanks to the recession and housing crash) would have been necessary, or cut dividends.
The same argument implies that payments from a bank TO the Treasury would reduce payments from banks to bank industry shareholders (or increase payments from shareholders to the banking industry).
That's what's happening at BB&T (BBT). It plans to pay back $3.1 billion to the Treasury. At the same time, it will issue $1.5 billion in common stock and cut its dividend by $0.725 billion per year. In two year's time, the combination of those actions will raise $2.95 billion.