Lumb's not coming back for a while, he's going to play in the T20 World Cup. Dimi is out injured until at least June, Jones is unlikely to play until June/July at the very earliest and I don't see Herath doing much better than Briggs who has started the season well.
Big mistake to let Tahir go (which he'll no doubt prove in the Championship match this week). I'm worried, it already looks like the season is going to be T20 or bust which is a shame as although a bit of fun, it's not really cricket.