Raheem Sterling has been left out of the England squad for the forthcoming games against Ukraine and Poland, despite his electric start to the season.
The Chelsea forward scored twice and assisted once in last Friday's win over Luton but it has not proved enough to catch his manager's eye.
"I didn't want to leave any attacking players out," said Southgate. "There are a lot of competition for places in that area behind the nine.
"I am really happy to see him do well for Chelsea, but everyone has started the season well. Raheem's not particularly happy with that."
It is better news for Levi Colwill however whose form at the back for the Blues has been rewarded with a first call-up to the senior side.
Speaking of Colwill along with Arsenal's Eddie Nketiah, Southgate said: "Two young players who are doing very well and have done well with our junior teams. Levi had time with us in the summer.
"I didn't want to move away from our squads at Old Trafford [earlier this summer]. It's only been three games into the season."