Allen injured his hip last week against the Raiders, but an MRI came back negative on Monday. The Colts expected Allen to be healthy enough to practice on Wednesday, but he did not participate. Allen also did not practice on Friday, which is usually a very strong sign that a player won't play on gameday.
Allen's likely inactive status for Sunday means that fellow second-year tight end Coby Fleener must step up. Fleener has been a disappointment since the Colts selected him with the No. 34 overall pick in the 2012 NFL Draft.
While Allen has been downgraded, rookie running back Kerwynn Williams has been upgraded. On Friday, following the unfortunate news that starting back Vick Ballard's season is finished due to an ACL injury suffered in practice, the Colts promoted Williams from the practice squad to fill Ballard's spot on the active roster.
Vick Ballard was placed on season-ending injured reserve on Friday.
Williams can also return kicks and punts, which is fortuitous for the Colts as returner David Reed will miss his second consecutive game with the Colts due to a concussion.