Yes, if you don't want to pick the player up now, or if you want to just keep track of a player, you can add them to your watch list. Click on Team » Watched to view your list. You can add players by clicking on the star icon to the left of where they appear. You can remove players by clicking the red X next to their name on the Watched page at any time.

A watch list will keep tabs on players you are interested in having on your team but you may not be ready to add them quite yet. Click the star button next to the player to add them to the watch list and access this list from Team » Watched. You can add players to watch from that page as well.