很好的一个帖子。j0n6dj2y2w给其它帖子很多好的建议。相信j0n6dj2y2w知道如何处理。很高兴这个“危机”解除了。
个人观点,既然这个同事有能力,作为team lead, 不应该给不客观的评价。
在需要的时候可以说“he/she gave us great help when xxx is absent. His effort is very important for us to keep xxx project on schedule. The team appreciates his help in xxx". It is pretty typical for a normal expression of "thank you".
如果有其他考量,可以不必过分赞誉,但不要刻意贬低,也不必要指证小的错误。Some people better to avoid, some people can be your supporter. But try not to mistreat people.
再有,if you want to kee your current position safe, try to go up.