Beasley is pretty good as a slot receiver. So on the good side, he's a known quantity. If getting 55 catches, 500 yards and 3 tds a year is what you're after, go get him.
On the bad side, however:
1. Considering the way he left Dallas, seriously doubt the coaches want him back. Guess he could apolgize and "all will be forgiven" but I don't see that.
2. He's 32 years old, also doubt he'd not want a multi-year contract and at that age it's a risk.
3. As a 10 year vet he has a minimum salary of over $1 million a year. Don't see Dallas, with their cap problems, they can pay a part time receiver that much.
4. His average production is a bit less than you want from your slot receiver, after 10 years he's not likely to start getting more production.
5. Assuming a starting receiver lineup of Lamb, Gallup and Wilson, plus Schultz, not to mention having Pollard and Zeke out of the backfield, doubt he'd get that many looks to justify a $1mil salary.
Always plenty of "undersized" undrafted receivers in any given year, pick one....