I just received an email last night from the Senior Collaborator (SC) who I recently submitted a grant with, inviting me to co-PI a second grant for the July round. I think the grant we submitted already is a really solid, but the process of submitting it was not exactly smooth and SC's slow movement on several fronts caused some issues for me. Now SC is proposing a project on a group of organisms I have never worked on and have never been interest in previously. SC has worked extensively in this group and the combination of SC's work and the approach that I take in my research would produce some interesting results.
With that said, I am already committed to submitting a grant with a different collaborator in July to a different program. If by some miracle the grants I have out now and the one I am committed to all get funded (just work with me here for a second) I would have three unrelated projects going on in the lab. If I add in the one SC is proposing that would make four, with only two of those central to where I see the lab going in the long term.
One approach would be to jump on with any opportunity and try and make the most of it, knowing that the success rate is low and I need to build up the lab with whatever projects fly in the short term. I understand that side, but an alternative is that spreading the lab all over the map is not the best strategy, particularly through collaborative projects with a senior co-PI. In the tenure process one might argue that I needed a senior colleague to get the grants funded and ended up chasing the money rather than the stated theme of the lab. This is not like saying you are going to work on X in chimps and end up doing Y in apes - more like Y in jellyfish. Nevertheless, it would be productive and using an approach that is central to the lab.
It could all be justified depending on the hat I am wearing since my work bridges several disciplines, but the combination of spreading the lab thin and dragging SC through another episode of grant writing has me weary of this project. But do I have the luxury of saying no to a current collaborator and a project with potential? My magic 8 ball keeps coming up "Cannot predict now".