The 4.44 ERA in 52.2 IP is not ideal. Expect those numbers to come down. His strikeout percentage is up this year and his walk percentage is around his career numbers. The thing that seems to be getting him this year is his homerun to fly ball ratio. His FIP and xFIP numbers are good and below his ERA at 3.33 and 3.27 respectively. I wouldn't expect the Athletics to sell low on Sonny Gray. He's controlled through the 2020 season.
The 4.54 ERA in 83.1 IP is ugly. It's made even worse by the fact that his FIP (4.58) and xFIP (4.02) don't give much hope of that dropping. Like Gray he's giving up the long ball more than usual this year. His strikeout rate is also down. Which is probably the reason his advanced numbers are betraying him. His career numbers indicate his ERA should be in the low-to-mid three range. This might just be a down year for Cole. He's also controllable through the 2020 season.
Quite possibly the most talked about name in Astros pitching trade rumors. He is off to an even worse start than either Gray or Cole. His ERA is 5.07 in 81.2 IP. His FIP (4.36) and xFIP (4.40) are lower. He's giving up more home runs this year. His strikeout rate is up, but his walk rate is also up this year. He's a free agent after the 2019 season.
Finally! Someone with an ERA (3.80) below four in 92.1 IP. FIP and xFIP both like Archer to get better this year. His strikeouts are up and his home run rate is down. Archer will be expensive. They turned down an offer of Kyle Tucker, Francis Martes, David Paulino, and two other prospects in January. He's controlled through the 2020 season.
Who are the other pitchers you're interested in that we haven't heard rumors on yet?