Sprint's (S) - Get Report slowdown game deflated an early Nextel Partners( NXTP) rally.

The big Kansas telco said Wednesday morning that it would seek third-party appraisals on the buyout value of its 32%-owned Nextel Partners affiliate. Nextel Partners shareholders have a so-called put option that would require the newly merged Sprint Nextel to acquire the affiliate. The put process involves three sets of appraisers and could take four months or more if challenged, Sprint has said.

Sprint's statement, with its promise of a long, contentious process, threw water on Nextel Partners' Wednesday rally. The stock rose 4% early Wednesday, reaching a 52-week high at $27.40, after

TheStreet.com

reported that Sprint had hoped for a quicker resolution to the standoff. Sprint had been hoping to

bypass the appraisal process through a negotiated deal that could fetch around $30 a share for Nextel Partners, according to people familiar with the company.

But in a press release Wednesday, Sprint says it is opting for the formal put process rather than a negotiated deal. Still, the company cautions that it reserves "the right to take any action in the future that it determines to be in its best interests."

Sprint's acquisition of Nextel last week was supposed to launch a new wireless powerhouse that could better match up with telco giants like

SBC

( SBC) and

Verizon

(VZ) - Get Report

. But instead, the combination seems to have unlocked the gates to an affiliate mess.

Some of the affiliates have charged that the Sprint-Nextel combination violates noncompete agreements by creating an entity rivaling the small telcos in some markets. If Sprint decided to acquire its remaining affiliates, not including Nextel Partners, it could face an additional $12 billion tab, say analysts.

Shares of some of Sprint's affiliates have risen this year -- like

UbiquiTel

( UPCS) and

Alamosa

( APCS), up 23% and 37%, respectively -- as Wall Street has gotten behind the takeout speculation.

Sprint obviously doesn't like the way affiliate valuations have soared this year. CFO Paul Saleh said Tuesday that the company has had discussions with all the affiliates, but "we haven't been able to reach acceptable terms."

Last month, Sprint settled one dispute by offering $1.3 billion to buy Lake Charles, La., affiliate

U.S. Unwired

(UNWR)

. Earlier this month, Alamosa sued to stop the big merger, saying Sprint's takeover of Nextel would damage exclusivity covenants.

Two affiliates, IPCS and UbiquiTel, are under a forbearance agreement to postpone legal action until January.

All the unfinished business may also hamper Sprint's marketing plans. Sprint is under the gun to iron out the affiliate issues so it can launch its new brand with a massive advertising campaign scheduled to begin as early as next month.

Sprint shares rose 68 cents to $26.54 Wednesday, and Nextel Partners dropped 2 cents to $26.09.