The Pittsburgh Steelers could re-sign Brett Keisel and do it for a relatively cheap price. According to Over the Cap and SB Nations Behind the Steel Curtain, Keisel could be brought back under the Minimum Salary Benefit or MSB, which was a clause added in the 2011 collective bargaining agreement.
Basically the Steelers could, potentially, sign Keisel to a one-year contract for the veteran minimum amount for his level of tenure ($955,000) along with a $65,000 signing bonus, and have it count as $570,000 against the 2014 salary cap.
All players with at least 4 credited seasons are eligible for the MSB. However, to qualify for MSB treatment your contract has to meet specific criteria, explained as follows:
1. The contract must only be 1 year in length
2. Additional compensation can not exceed $65,000 in 2013 (this number rises by $15,000 every 3 years, with the next increase set for 2015), and that includes bonuses from other teams
3. P5 guarantees can not exceed the P5 salary of a 2nd year player, which is $555,000 in 2013