A couple of other free-agent fallback options might be Chris Mihm and Michael Sweetney, with Ron Tillery reporting that Grizzlies representatives have attended workouts for each player in Vegas.
Is there anything promising here?
Mihm has size and youth on his side: He’s only 27 years old and is a seven-footer who weighs in at a solid 265 pounds.

Mihm missed all of last season with an ankle injury, but his rebound rates from his previous four seasons (14.2, 15.1, 19.8, 16.0) are solid. Mihm doesn’t have much of a post game, but, with Pau Gasol as the primary interior option, that wouldn’t be a problem with the Grizzlies. He can knock down short jumpers and finish plays around the rim, and move well without the ball, which makes him a useful secondary player offensively.
During Mihm’s two full seasons with the Lakers, he’s averaged about 10 points and 6 rebounds a game in about 25 minutes a night. He’s also shot 50% from the floor.
Mihm could be a promising, affordable option for the Grizzlies this summer, with last season’s injury potentially holding down his asking price and the Lakers’ situation — having Andrew Bynum in the middle and other needs to fill — making it unlikely they’d be willing to spend much to retain him.
For the Grizzlies, there are two big questions about Mihm: Is he fully recovered from his ankle injury? (And, is he more likely now to have further problems?) Does he fit the style?
If the Grizzlies are convinced that Mihm is fully healed and would be able to play in Iavaroni’s system, he could actually be a decent signing for a short-term deal (three or four years) at half of what Varejao or Darko might cost.
What about Sweetney?

The 24 year old forward is a very talented player, but, at 6’8” 270 pounds, he’s really struggled with his conditioning.
When he’s in shape and on the floor, Sweetney’s been a very solid scorer and rebounder on the block, but his career has been shrinking in inverse proportion to his increasing waistline. Last year, with Chicago, Sweetney appeared in only 48 games and played only 8 minutes a night.
At this point, you have to doubt Sweetney’s ability to stay in shape. If he could, he could be a nice player in some systems. But I don’t think it’s this one. I say pass on Sweetney.

Yes, I also have visited Cleveland many times, and there is a reason they call it the "mistake by the lake". However, if you are Varejao, would there be much difference between Cleveland and Memphis? Maybe he's a big fan of the blues and Stax. I guess anything is possible.
I like the idea of a "defensive" center like Haywood. It just seems that Washington is really shopping Etan Thomas for a reason - it seems that Haywood fits into their plans, too.
Free agency blows. Especially this year.
Navarro is a good 1/2 guard who can really shoot it and is from Spain. He has played really well in some of the international tournaments and made a name for himself. He and Oau are good friends, so I think Pau has probably lobbied Wallace to get him. Could we use him - yeah, I think he's be a good backup for Mike Miller. Another shooter would be great. But do we really want to take on Etan Thomas's contract?