Welcome to the Forum.
What's his current overall rating? When making trades, the CPU ultimately judges the value of players by the overall rating and it's rare that you'll get them to accept a package of lesser value unless they have a high interest in the players you are offering (as indicated by the Interest meter).
A good place to start is to look at players who have an overall rating that is identical to Dalembert or are slightly higher or lower. The next thing you will need to look at is the contracts. When you're trading over the cap, you need to get the salaries as close as possible as the salaries going one way cannot exceed 125% of the salaries coming the other way.
For example, if both teams are over the cap and you're trading a player with a salary of $5 million, the player coming the other way must have a salary of at least $4 million or at most, $6.25 million. You can check those figures by multiplying by 1.25 (125%). As you can see, it's easier if you can get the total salaries on both sides as close as possible so you don't have to worry about the 25% leeway.
If the salaries don't match, you'll need to add other players to the deal to make it work under the salary cap. If the CPU team has a free roster spot, you can sometimes use that advantage by giving up three players for two or two players for one. As well as matching salaries, take note of the players' overall ratings. Once again, the CPU uses the overall as a point of reference in determining a player's value so it usually comes down to matching the overall ratings on both sides.
Basically, you want to offer the CPU equal value or if you're desperate to get a deal done, a couple of points in their favour. Adding the extra players in the trade helps balance the offer and can allow you to offer a lesser player at the heart of the deal (eg a 77 overall for a 79 overall) by making up for it with the other players in the deal (eg a 71 overall and a 70 overall for a couple of 68 overall players).
The CPU will very rarely accept a deal that does not favour them when it comes to the total of the overall ratings and if they're not very interested in the players you're offering, they'll also reject deals of equal value so again, if you really want to make a deal you can give the CPU more incentive by accepting a couple of players who are rated a bit lower. Note that this does make it more difficult to complete subsequent trades and obviously depletes your talent pool a little but hopefully the player you've acquired will offset that.
Hope this helps!
