Loneliness was the worst part, Dan Haren said. At his lowest point, Haren walked off the Nationals Park mound to boos from home fans – “I don’t wish that upon anybody,” he said – and carried the worst ERA in the majors. His wife and two young children were at home in California. He agonized about what his teammates thought about his performance. When he went home, his house was empty, aside from him and his nasty thoughts.

“It was really, really difficult,” Haren said. “Most guys have their families where they are, so I’m not going to bug them. The majority of my time was spent alone. Those times where I was struggling on the mound, it was really compounded by just kind of being alone. My life revolved too much around baseball. It didn’t affect how I was pitching. But it made in between pitching and after the games more difficult.”

Saturday in Arizona, Haren, 33, will make the final start of his season. He knows it will almost certainly be the last time he wears a Nationals uniform. He signed a one-year, $13 million contract last December, a reward for being one of baseball’s best pitchers for a half-dozen seasons. He spent the first two months of the season as perhaps the worst in the league. He’ll take the mound Saturday with a 9-14 record and a 4.87 ERA.

Overall, Haren’s season was a disappointment – he also knows there will not be another $13 million contract waiting for him this winter.  But Haren is proud of how he turned his season around after he went on the disabled list “for more mental reasons than physical reasons,” he said. He reduced his ERA by almost two runs. For a decent stretch, he was the Nationals’ most reliable starter. His emergency save to cap the Nationals’ 15-inning win in Atlanta was one of the highlights of the season.

Haren enjoyed his final two months in Washington. At the start of the year, at times, he wished he could just go away.

“I mean, emotionally, I didn’t even want to come to the field sometimes,” Haren said. “Or when I got to the stadium, I would want to go hide in the weight room. I was embarrassed to show my face around the clubhouse. I didn’t want to come to the field. I wanted to just be alone. I’m proud of the way, coming back after the DL stint, I was successful. I kept us in the playoff race for a month or two while I was pitching really good. We made a good run as a team. I’ve regained the joy of coming to the field and watching the game and having friends and stuff.”

Haren prepared himself to pitch on the East Coast for the first time, but it was more difficult than he expected. His wife, 5-year-old son and 3-year-old daughter visited him twice during spring training and four times during the year. His boy started kindergarten with him on the other side of the country.

“From a personal standpoint, it was really tough,” Haren said. “I hadn’t been away from my kids. It’s a year of their lives I’ll never get back. From that standpoint, it’s sad. But one day, they’ll understand what I had to do to make a living. I think they’ll get it.”

Haren expressed his appreciation for General Manager Mike Rizzo, who even in his worst moments told Haren he believed he would rebound. Haren drew motivation, he said, in trying to perform better for Rizzo.

Haren would prefer to return to the West Coast in free agency, but he understands it may not be his choice.

“With the year that I’ve had, I’m not going to be able to just pick and choose where I want to go,” Haren said. “If I was 18-5 with a 3.00 ERA, I could choose to play on the West Coast. But when you have a 5.00 ERA, there might be only options to go Midwest or East Coast.

“I’m a pretty realistic person. I think in general, players get paid on what they’ve done, not what they’re going to do. I’ve made a lot of money this year. But also, I’ve accomplished amazing things from the past eight years. That said, next year, I’ll be judged a lot on how this year went. Obviously, my salary is going to go down. I’m aware of that. I’m not looking out to go get a multi-year deal at $12 million per year. I’m realistic to what my value is going to be next year.”

Haren will end his season with an odd statistical blend. Two of the most predictive peripheral measure are strikeout-to-walk ratio and WHIP (walks and hits per inning pitched). Based on those stats, Haren’s struggles seem improbable.

Haren posted a 4.87 K/BB ratio, sixth best in the majors, sandwiched between Chris Sale and Felix Hernandez. Every other pitcher in the top 27 of strikeout-to-walk ratio had an ERA of 3.71 or better. Haren punched up a 1.26 WHIP, not great but not terrible – 48th out of 81 qualified starters, essentially the same as Gio Gonzalez’s.

His problem was easy to diagnose. Haren gave up 1.55 homers per nine inning, worst in the National League. He gave up fly balls with the fifth-highest frequency in the majors, which is on him. His fly balls turned into home runs at a 13.5-percent clip, ninth-highest in the majors. That’s a little bit of bad pitching and a little bit of bad luck.

After he returned from the disabled list, Haren attacked the problem. He prioritized keeping his pitchers down. He told himself to make sure any mistakes were in the dirt, not at the letters. It worked. Haren allowed nine homers in 14 starts after coming off the disabled list. He gave up 19 in 15 starts before.

“I just really got back to simplifying,” Haren said. “Not trying to think too much about speeds or anything like that. Just trying to go out and keep the ball down – actually trying to keep the ball in the ballpark. That was how I was getting burned. Very few percent of runs, in comparison with other pitchers, were manufactured against me this year. A lot had to do with the home run, and trying to minimize that.”

The Nationals have gone 10-19 in Haren’s first 29 starts, but that is a little misleading. Haren has received the seventh-worst run support in the majors (though he has received slightly better run support than Stephen Strasburg has). The Nationals lost three times when Haren allowed two runs, once when he allowed one run and once when he allowed no runs.

Haren’s year in Washington did not unfold as he hoped. Despite his trials, both personal and professional, he doesn’t regret signing here.

“This was my fifth team in 10 years,” Haren said. “Chances are, I’ll have six teams in 11 years. It’s not fun going into new clubhouses and trying to make friends and win over fans and stuff like that. I liked it. I liked playing there. Especially the last couple months, the way we’ve been playing, just the vibe of the stadium and getting more comfortable with the guys, it’s been great.”