Stephen Strasburg and Dallas Keuchel are hitting their stride

Stephen Strasburg has been strong since coming off the DL. Ross D. Franklin/AP Photo

In a battle of division leaders in Houston on Thursday night, we had a battle of aces on the mound, both of whom have been changing things up since coming back from injuries.

Stephen Strasburg faced the Houston Astros in his second start since returning from the disabled list, and he pitched another gem, throwing six scoreless innings with seven strikeouts. The Washington Nationals ace has pitched six innings in both starts since returning, with 15 combined strikeouts and only two walks.

Strasburg has used his changeup as a weapon, throwing it more often than usual (more than 20 percent in both starts) and getting seven strikeouts with it in two games (he recorded 10 strikeouts with it in his final seven starts before hitting the DL). He has struck out 35 percent of the batters he's faced since returning, a big spike from his pre-DL rate of 28 percent.

What's more impressive is Strasburg's ability to turn it up against the good teams. It's the fourth time he has faced a team that currently holds a playoff spot -- and he has been great in all four starts. He has a 1.29 ERA against the Dodgers, Cubs, Diamondbacks and Astros, compared to a 3.43 ERA in his starts against every other team.

And then there's Dallas Keuchel. The Astros ace made his sixth start since he returned from the DL.

Unlike Strasburg, Keuchel's first three post-DL starts weren't good -- he didn't last more than five innings in any of them, and allowed a total of 14 runs, including eight runs in a clunker a couple weeks ago against the White Sox.

He allowed two earned runs in seven innings on Thursday, his third straight solid start since then, and he has pitched into the seventh inning in three straight outings.

Twenty-two percent of his pitches have been changeups in the past two starts, a huge increase from his early-season numbers (13 percent in his first 15 starts). That has led to lots of ground balls, including a season-high 18 of them on Friday against the Athletics. And hitters have whiffed on more than half of their swings against his changeup the past two games, up from 39 percent before last week.

The Nationals appear to be settled into the second spot in the National League, so Strasburg is looking to refine things heading into October. And the Astros are trying to hold off the Red Sox for the American League's best record, and Keuchel looks to be rounding into form entering the final month.